Advice on playing an evil character (In a good party)

[Lakaz]

So i recently rolled my first evil character. We're playing 4e and he's straight evil, (Which i think is equal to Lawful Evil in other settings). He's a gnome avenger of Vecna, sent by a now-dead Vecna cult in far off lands to spy on the ioun-worshipping nation that is the campaign setting, and told to go undercover and await further orders which will never come, as the cult has since been wiped out without his knowledge.
I realised at this point i have no real idea how to pull this off without getting killed rather quickly. My character is meant to be undercover, not advertising his Vecnarian religion and even hiding it, but he needs to use his holy symbol of his god to use any of his powers, which will likely be required once combat starts up, and he'll show up on Detect Evil spells, so i have no idea how to effectively hide this without lugging around a lead sheet.
So i figured i'd come to the giant in the playground forums, home to the all-knowing knowing lords of roleplaying games, to see if you have any ideas.

Tl;DR: I rolled an evil religious character in an all good party. How do i not get found out and avoid generally acting stupid-evil?

[Citrakayah]

4e doesn't have detect evil, as far as I know.

[Kid Jake]

I've been told Kavos in my Pathfinder journal is a pretty solid example of non-stupid evil so I'll use him as an example.

Kavos is a LE Cleric of Asmodeus and really only cares for people based on what they can offer him; however he projects the APPEARANCE of somebody who genuinely cares about the little man to deflect suspicion. He's as generous as he can afford to be; offers healing and succor to those that need it and pretends to worship Pelor as a cover. In most respects he'd fit in perfectly with your average good party.

He's also pragmatic to a fault. Threaten his interests and he'll poison you under the guise of helping. Have something he needs and he'll turn you into a smoking corpse without a second thought. If it ever comes down between you and him he's going to unleash the full powers of hell to make sure he's the one that walks away. But he does it in secret. He's all smiles and apologies in front of everyone, he only whips out the evil guns when he knows he'll be the only one left to describe the incident afterwards.

[gom jabbarwocky]

I can probably guess that the best advice will be to the effect of thus;

"I was going to roll up an Evil character in an all-Good party. What should I do?"
"You shouldn't."

But you did. So what now? First, make sure, OOC, that this is cool with the rest of the players, that you can all deal with it. Second, play it strictly Lawful Evil - you're bad, but you still play by the rules. Like FDR said, "he's a bastard, but he's our bastard." The other PCs don't have to like you, but you keep your word and you'll stand by them in a fight.

Either that, or just fake it and hope no one put ranks into Knowledge: Religion (do skills in 4e even work like that?) "Yeah, no, this isn't a holy symbol of Vecna, but I can see how you would be confused. I worship Vecna's brother, Gummo, who's symbol is very similar."

[Red Fel]

Tl;DR: I rolled an evil religious character in an all good party. How do i not get found out and avoid generally acting stupid-evil?

Does he like the party? It's a simple question. Does he like the other PCs, and do they like him? Are they friends? If they are, a reveal is appropriate.¹ Remember that "Evil" doesn't mean "friendless." In fact, Evil with friends is even more terrifying than Evil without, because you can only imagine what they'll do if you hurt their friends.

Now, I don't know 4e, but Vecna in previous editions has been all about secrets. So you'll have to be a bit aloof. And just because you've come out to your friends doesn't mean the vast majority of the population needs to know. The trick with the reveal is to not make a big thing of it. Generally, if you play it up like a big, tragic secret, they'll take it with emotional impact; if you play it off the same way you'd play off, "Yes, I'm a gnome, so what?" It becomes easier to take, simply because of the casual bluntness.

That said, if you really intend to keep it secret, find a way to come across as Neutral. That is, can a Cleric of Vecna be anything other than straight-up Evil? If so, pretend to be that. As a Cleric of an Evil god, you'll still ping as dark-and-naughty, but you can claim it's a function of your deity, not your personal beliefs.

¹ Exception: If there's a Paladin in your party, one of you pretty much has to change characters. Again, I don't know 4e, but if Paladins are anything like their earlier counterparts, he literally can't stay in the party with you and keep his class features. One of you will probably have to reroll.

[Lakaz]

First, make sure, OOC, that this is cool with the rest of the players, that you can all deal with it. Second, play it strictly Lawful Evil - you're bad, but you still play by the rules. Like FDR said, "he's a bastard, but he's our bastard." The other PCs don't have to like you, but you keep your word and you'll stand by them in a fight.

I have checked oocly that it's good with all the players (And the GM for that matter). They seem quite happy with the idea provided i don't go starting any PVP or trying to derail things. This is more or less why i decided to introduce the "He's under orders to stay undercover, and isn't going to get any to the contrary any time soon" part of the backstory. He's lawful evil and he's going to abide by the last word he's received from his cult as best he can. Which means no stabbing paladins for being good-aligned, no TPK's, no derailments that can't be avoided.

As for Red Fel's advice about whether or not he likes the party? I actually like that idea, yeah. Most of the characters are fairly devout, and while none are full-on paladins we've got at least one Invoker, which from my understanding is pretty close (Although without that troublesome "Falling" mechanic). As a result, it's unlikely they'll be too happy with him, and it'll take a lot of diplomacy to let him stay after the reveal, but as you said, i'll try to minimise the emotional impact of The Big Reveal(Tm) and build friendships prior to it to make them... less inclined to kill me for it XD

[Bob of Mage]

First off build a good cover story. You need a fake god to worship so start there. Make something up like the minor god of Muderhobos (we'll call him MH as a placeholder). Now MH stands for a wide ranges of things which allows your actions to be what every you want as long as you go around fighting monsters and stuff. Set him as Neutral so if it becomes clear that you might be evil your cover is safe (you just happen to be willing to do some of your gods darker work).

This cover also meshs with being a minion of Vecna. First it's a front which is about keeping things hidden, second it allows you to hunt down hidden things with no one rasing an eyebrow. This could also be part of a larger scale plan with other follower of Vecna also spreading MH's faith. Thus Vecna can use unwitting "heros" to do his bidding.

For the holy symbol you can have the Vecna part of it hidden (again fitting his faith). Have the symbol of MH on the front, but have a disk in back. This disk is really two peices of metal fused together with Vecna's symbol hidden inside. Thus you can hold up Vecna's symbol and no one will know it's there but you (that is unless they have some power tools handy which shouldn't be an issue).

Finally you should do whatever helps the party. Afterall it's part of your cover and it won't hurt your hidden master. In fact knowing Vecna it will advance his plan somehow. If the party is unlikely to use the old man as bait for the ghouls then don't push the issue. In fact you should likely keep that plan to yourself unless you know the other PCs won't take too much issue with it (maybe they might take it as a joke).

One finally thing is that you don't need to be Lawful Evil to work well with others. In fact being Neutral Evil might work better since you are going to have to lie your ass off most of the time (NE will still be loyal to friends, but won't really feel the need to keep thier word to everyone, such as thier enemies). Good idea to take some bluffing skills.

[Tragak]

I have checked oocly that it's good with all the players (And the GM for that matter). They seem quite happy with the idea provided i don't go starting any PVP or trying to derail things.

And that's all you need

A lot of the specifics that have been covered are very good (Your Villain Protagonist legitimately cares about the other players' Hero Protagonists, just not nobody else, Pelor help anybody your guy fears to be threatening his friends; Vecna is literally the god of secrets, so of course his cult would order your VP not to rock the boat...), but ultimately the fact that everybody else at the table seems to be playing in good faith means that any complications in-game will be resolved without a problem arising out-of-game. There are no problems with game mechanics, there are only people who use game mechanics in ways that cause problems (intentionally or otherwise), and it doesn't look like you need to worry about that.

Somebody playing in good faith won't cause a problem regardless of whether his character is LG or CE
Somebody not playing in good faith will cause a problem regardless of whether his character is LG or CE

I've run an amazing game where the characters were LG, CG, and CE, and the only thing that was required for the set-up to work was: the players agreed out-of-game to make the set-up work.

[Gavran]

As a fellow 4E player: Detect (Alignment) doesn't exist at all to my knowledge. If it does, it's certainly not something common or needed on any characters. Likewise the 4E alignments for whatever reason are more simplified, that doesn't mean you can't pick Evil and be CE or LE.

On your implement, well, you're totally fine. Options include:

- Your holy symbol isn't a sticker that says "I <3 Vecna!". The rules say "A holy symbol represents your deity and takes the shape of an aspect of the god." Personally I would say that deception and secret keeping are both aspects and representations of Vecna, and as such a symbol of Ioun that -you- know is for Vecna would be entirely sufficient.

- You can have more than one "holy" symbol, and you never have to share the real one. The rules say "Unlike other implements, you need only to wear a holy symbol for its property or power to function." Note that they also say if you have multiple holy symbols, none of them work, but I see no reason you can't have a very much ordinary symbol fashioned to resemble Ioun's holy symbol. Either way, you can certainly just hide your holy symbol.

- There are also (magic) weapons that work as holy symbols.

- It is entirely possible (even sometimes ideal) to play an Avenger that chooses no Implement powers (and thus no holy symbol).

- You can multiclass or otherwise take feats to use some other kind of Implement instead of a Holy Symbol.

Just as some general things others have talked about already: an acolyte of Vecna is acting entirely in-character to do basically whatever it takes to keep that fact secret. This gives you a lot more leeway than say, an undercover paladin of Pelor in an evil party. Evil doesn't mean kitten sacrifice. Evil doesn't mean you have to betray everyone at some point. Invokers actually contain something along the lines of "a divine spark" and are probably the least faith-adherent of the Divine classes, though in 4E no Divine class loses their powers under any circumstances. Vecna's brand of evil is much more about being self-interested and secretive than spilling the blood of the innocent. Even disregarding that, as an individual follower of your deity it's entirely up to you how Evil you are (or even if you are.)

4E is the edition of mutable fluff. Bring this discussion on over to our subforum if you want, the people there are great at working with alternative fluff to help make cool ideas work.

[Frozen_Feet]

Having to use your holy symbol is something of a bother. What is Vecna's symbol, anyhow? Is there any way you could perhaps spin it as the symbol of some really ancient Gnome God? Then every time someone accuses you of worshipping an evil deity, you can shout "How dare you! This is ancient symbol of peace and love truth and knowledge of my people! You only think so because dirty humans/[insert accuser's race here] appropriated it for their vile uses! It's because of your biased culture that many innocent gnomes are harassed and bullied each year! You racist/anthropocentric/supremacist/oppressing scum!"

After you've thoroughly shamed anyone suspecting you, you just need to act like a normal, law-abiding citizen when people are watching. You get extra points if you can somehow manage to appear more friendly, polite and whatever to other people. Never forget to rub it in for the so-called good characters. Take example from, say, Dexter in his eponymous TV series.

Your religiously-motivated evils should only come up if someone catches you red-handed, or your religion's mandates necessitate direct opposition against your so-called comrades. With your evil cult having suffered a critical existence failure, the latter should not be a problem. Slaughter goats and virgins for your dark master in the peace of the night or in your own house during downtime and cover your tracks.

[LibraryOgre]

Leaving aside the mechanics, consider that your god is a god of secrets.

You are with these people because they are useful. In time, you may come to care for and respect them, and so may act somewhat altruistically towards them. There's a bit of enlightened self interest in this, too (after all, if the fighter is healthy and likes me, he'll be able to help keep me safe), but you might do things that conflict with your alignment but only in the context of certain people; that's part of alignment's flexibility. Evil is also very much "the ends justify the means"... and those means might occasionally involve kissing puppies and snuggling kittens, if it gets you what you want.

But, since your ends justify your means, consider doing some things outside of the party's knowledge. Did a minor villain get away? Hire a "bounty hunter" to kill him. Do you need some equipment that is being sold at too high a price? Hire some thieves to acquire it for you. You don't have to do everything in front of the other characters, even if you frequently do it in front of their players.

For your holy symbol? Consider something abstract and flexible, so you can claim power from any number of things (heck, Ioun's holy symbol looks REMARKABLY like an eye in a stylized hand). "I serve a god of knowledge" is true enough, but it's not the whole truth, nor does it need to be. Cultivate an air of mystery around your religion. Blunt questions are ignored or evaded. "Do you worship Ioun?" "Some call him that, but his true name is to sacred to be spoken."

[jedipotter]

Well, just don't do anything Stupid Evil or Crazy Evil. Just act like a fairly normal character would.

You can ''hide'' your holy symbol well enough. Wear it around your neck and touch it to cast a spell...otherwise tuck it away. Not like you will wave it in someones face. It's just a hand and eye, you could say it's ''Eye-Bee the gnome god of seeing hands''.

In general, you want to just not show your evil....but then there really is no reason too. You don't need to go slaughter innocents and drink there blood to be evil. You can just, take a nap, and still be evil.

Sure, your always looking for a good way to ''cheat'' or ''steal'', but that does not have to show much. You'd steal some thing of value, if you could. But your not going to steal from your group, wave it in their face and be all like ''haha".

Ok, in combat you could be a bit ''cruel'' and kill people....but that is kinda normal. The paladin that gets covered in blood when he beheads an orc is not going to say ''oh, your fire spell looked like it hurt the poor orc''.

Agent Ward, from Agents of Shield is a good example. Or Vala from Stargate. Or Todd from Stargate Atlantis. Or Captain Hook on Once Upon a Time. Or Garick on DS9. They are all evil, but they don't do anything to harm their ''group'' (most of the time).

[Lakaz]

Having to use your holy symbol is something of a bother. What is Vecna's symbol, anyhow? Is there any way you could perhaps spin it as the symbol of some really ancient Gnome God? Then every time someone accuses you of worshipping an evil deity, you can shout "How dare you! This is ancient symbol of peace and love truth and knowledge of my people! You only think so because dirty humans/[insert accuser's race here] appropriated it for their vile uses! It's because of your biased culture that many innocent gnomes are harassed and bullied each year! You racist/anthropocentric/supremacist/oppressing scum!"

After you've thoroughly shamed anyone suspecting you, you just need to act like a normal, law-abiding citizen when people are watching. You get extra points if you can somehow manage to appear more friendly, polite and whatever to other people. Never forget to rub it in for the so-called good characters. Take example from, say, Dexter in his eponymous TV series.

Your religiously-motivated evils should only come up if someone catches you red-handed, or your religion's mandates necessitate direct opposition against your so-called comrades. With your evil cult having suffered a critical existence failure, the latter should not be a problem. Slaughter goats and virgins for your dark master in the peace of the night or in your own house during downtime and cover your tracks.

While i haven't seen dexter, that was somewhat similar to what i was planning to pull off. Shame everybody into being unwilling to point out you just stabbed the priest in the spine, 'cause they don't want to be accused of being Ioun Supremacists.
Not that i ever WOULD stab a priest in the spine, that would be horrible. Why would i want to kill the high priest of such a enlightened religion as his! Ahem, yes.
I doubt that the idea of spinning the holy symbol as a item from another god would work given how high some of the party members religion skills are, however i have to thank Gavran for the idea of having it be an Ioun symbol that is SECRETLY a vecna one. Perfect for a worshipper of the god... of secrets.
Multiclassing or taking feats to avoid use of the symbol is not an option, none of the players are really big into 4e as a system, we're all rather new actually, and we want to keep things as simple as possible (So single-class characters, and... well, if such a feat is in one of the 3 players guides, i haven't found it.)

As many have you have said, no- evil doesn't mean kitten sacrifice. The kind of evil this character is likely to go for is going to be very quiet, and very covert. It'll basically be praying to Vecna in private or at night, acting out if his hand is forced and slowly gathering blackmail materiel on every Ioun-worshipper in a hundred mile radius. I mean, they're champions of knowledge, why would they object to me releasing a little more knowledge into the world? >:D Issues could still arise if we were to say, run into a pack of undead (Who are associated strongly with vecna) or possibly another cult from the same god. THAT could get awkward...

[Gavran]

Mhm, I think that's my favorite option too really. I also like the hidden symbol because then it could potentially be found which could potentially lead to interesting RP, but for me personally I like the fluff that a holy symbol is really "anything that is symbolic to you of your god." And "This is the symbol of my god's most hated rival, subverted to conceal my faith while I steal the secrets of her followers in Vecna's name"... that just works. :P The feats and such I mostly just listed for mechanical completeness, since I got the feeling at least some of your group is new to 4E and may not be comfortable with the more fluid fluff my more fun ideas require.

Off-hand, I believe MCing into Invoker would probably give you other implements and should be a thing in whatever book Invoker comes from (PHB2?), but I wouldn't suggest it unless the group was fervently insisting that you can't use Ioun's symbol or conceal Vecna's. Also this is sort of off topic by now, but MCing in 4th is nothing like the take-a-level thing other editions too. You spend one feat, "a multiclass feat" to gain a few small things from another class, which qualifies you for that classes feats and paragon paths, but you don't get any more of their class features without taking the "paragon multiclass" option (instead of any other paragon path) or any of their powers without taking feats that let you swap one of your powers for one of theirs. The vast majority of MCs never go past the first feat, and the real "I am two classes" characters are Hybrids instead of multiclassed. Really, our little 4E subforum is pretty great. Not as active as other forums but there are lots of really helpful people. We like shepherding converts in too. :P So if at some point you want some perspectives on coming to 4th from other editions, make use of it.

[Frozen_Feet]

While i haven't seen dexter, that was somewhat similar to what i was planning to pull off. Shame everybody into being unwilling to point out you just stabbed the priest in the spine, 'cause they don't want to be accused of being Ioun Supremacists.

You get bonus points each time some other character exclaims "But some of my best friends are gnomes!" (etc.)

As many have you have said, no- evil doesn't mean kitten sacrifice.

Well it doesn't have to, but it's the fun part, you know? Along with kicking puppies and quoting blasphemous scripture, though I suppose your situation precludes the last one. Bummer.

Issues could still arise if we were to say, run into a pack of undead (Who are associated strongly with vecna) or possibly another cult from the same god. THAT could get awkward...

Remember to rehearse your "Undead are not necessarily evil!" and "I'm using necromancy for good deeds!" speeches well beforehand.

[Citrakayah]

Agent Ward, from Agents of Shield is a good example. Or Vala from Stargate. Or Todd from Stargate Atlantis. Or Captain Hook on Once Upon a Time. Or Garick on DS9. They are all evil, but they don't do anything to harm their ''group'' (most of the time).

Hold it right there.

Vala is not evil. At all. She's a thief, yeah, and a bit self-interested, but you are talking about a woman who was willing to sacrifice her life to destroy the Ori's Supergate. Vala is willing to put herself in danger for ideological reasons.

Todd is evil, yes, though personally I'd argue that he's starting to get to the point to where he might start to slide towards being neutral. If memory serves, novel-canon has the Wraith's requirement to feed on humans get removed.

[kyoryu]

Remember that evil is all about *self-interest*, not *sadism*.

If you've fallen in with a group of powerful people that you can work with to get your goals accomplished, the *smart* thing to do is to give a little bit here and there so that they continue to help you reach your goals.

[jedipotter]

Vala is not evil. At all. She's a thief, yeah, and a bit self-interested, but you are talking about a woman who was willing to sacrifice her life to destroy the Ori's Supergate. Vala is willing to put herself in danger for ideological reasons.

Well, it's just one act. Is that enough? Otherwise she lies, cheats, steals, even kills to get what she wants. It sure is easy to see that she is very, very selfish and only cares about herself. Sure she likes Daniel, and the rest of the team is ok, so she won't betray them or try and hurt them. But would she steal from them? She has done so many times(and been caught a couple) Would she try and get a good side deal to get something for herself?

Sure, she becomes more good as the seasons go on, but don't forget Vala was the one in the Super Soldier armor that left the whole crew of the Prometheus to die in space...just so she could make some money. Mass Murder to make money is quite evil.

Todd is evil, yes, though personally I'd argue that he's starting to get to the point to where he might start to slide towards being neutral. If memory serves, novel-canon has the Wraith's requirement to feed on humans get removed.

Todd is not evil as he feeds on people, he is evil as he only cares about himself and his people. He ''works'' with the humans, only as long as they have the same goals. And they really have to watch him, as he is not on their side.

And that is the point of both. They are both evil characters, that work with the mixed group of alignments. They don't just walk over and ''killz everyboz as I'm evilz''....they work with the group...but you'd be a fool to trust them.

[LooseCannoneer]

Kill everyone until you get killed, then roll up a new character.

In all seriousness, Bluff is your friend. Bluff is who you took to the prom. You have married Bluff. Short of Vecna, Bluff is your #1 ally.

Memorize these words for if you ping as evil to anyone: "I was cursed as a child by an evil cult devoted to causing chaos by appearing as evil. The cult is dead, but I'm still cursed. Don't continue their goals for killing me."

Anyone capable of detecting evil wouldn't kill someone because they were tortured and cursed as a child.

[LibraryOgre]

Anyone capable of detecting evil wouldn't kill someone because they were tortured and cursed as a child.

Or... maybe not...

[LooseCannoneer]

Or... maybe not...

This is why Diplomacy is your #3 ally, following Vecna and Bluff.

[Citrakayah]

Well, it's just one act. Is that enough? Otherwise she lies, cheats, steals, even kills to get what she wants. It sure is easy to see that she is very, very selfish and only cares about herself. Sure she likes Daniel, and the rest of the team is ok, so she won't betray them or try and hurt them. But would she steal from them? She has done so many times(and been caught a couple) Would she try and get a good side deal to get something for herself?

She could have sided with the Ori, you know. She spent a long time in their galaxy, helping to fight them... honestly, saving the entire Milky Way galaxy multiple times really does make up for it.

Sure, she becomes more good as the seasons go on, but don't forget Vala was the one in the Super Soldier armor that left the whole crew of the Prometheus to die in space...just so she could make some money. Mass Murder to make money is quite evil.

Given that they got it operating again, calling it "leaving them to die in space" is a bit harsh. Also, character development.

Todd is not evil as he feeds on people, he is evil as he only cares about himself and his people. He ''works'' with the humans, only as long as they have the same goals. And they really have to watch him, as he is not on their side.

Killing people, even for food, is pretty evil.

And that is the point of both. They are both evil characters, that work with the mixed group of alignments. They don't just walk over and ''killz everyboz as I'm evilz''....they work with the group...but you'd be a fool to trust them.

I really doubt they'd let someone who they didn't trust become a full member of SG-1.

[goto124]

Does he like the party? It's a simple question. Does he like the other PCs, and do they like him? Are they friends?

It would really help a lot. You do have to go along with the rest of the party no matter what.

And it's nice to hear that your party allows a Evil character among Good ones. How long have you known the other players, and the DM?

Random idea: Whenever someone tries to cast Detect Evil, have an angel fly down from the heavens and gently remind the silly guy, 'Dude, that spell doesn't exist'.

[dream]

So i recently rolled my first evil character. We're playing 4e and he's straight evil, (Which i think is equal to Lawful Evil in other settings). He's a gnome avenger of Vecna, sent by a now-dead Vecna cult in far off lands to spy on the ioun-worshipping nation that is the campaign setting, and told to go undercover and await further orders which will never come, as the cult has since been wiped out without his knowledge.
I realised at this point i have no real idea how to pull this off without getting killed rather quickly. My character is meant to be undercover, not advertising his Vecnarian religion and even hiding it, but he needs to use his holy symbol of his god to use any of his powers, which will likely be required once combat starts up, and he'll show up on Detect Evil spells, so i have no idea how to effectively hide this without lugging around a lead sheet.
So i figured i'd come to the giant in the playground forums, home to the all-knowing knowing lords of roleplaying games, to see if you have any ideas.

Tl;DR: I rolled an evil religious character in an all good party. How do i not get found out and avoid generally acting stupid-evil?

You randomly generate alignment for D&D 4th ed? I thought it was always picked.

[Gavran]

You randomly generate alignment for D&D 4th ed? I thought it was always picked.

"Rolled" in this context means "created." I'm... a little surprised you hadn't heard it. I thought it was ubiquitous. I presume it refers to the rolling of attributes (not that you generally do that in 4E.)

[JusticeZero]

Just come clean. You can't keep it secret forever... Don't even try. A couple of encounters in, "Hey guys, I need to tell you something. I'm a horrible person, I follow a dark god, and i'm on your side. I'm not dumb enough to think that I can cross you guys without ending up dead, and I can use help covering this. My god is concerned about <BBEG's evil plan> because of <insert reasonable theological reasoning, which isn't generally hard with a lot of gods with broad interests>. Please don't hit me with any Holy Words or whatever. " Then be a good and trustworthy team member, albeit one with creepy contacts, whose suggestions for tactical ideas are a bit too careless with collateral damage.

[Cazero]

Just come clean. "I'm a horrible person, I follow a dark god, and i'm on your side. I'm not dumb enough to think that I can cross you guys without ending up dead, and I can use help covering this. My god is concerned about <BBEG's evil plan> because of <insert reasonable theological reasoning, which isn't generally hard with a lot of gods with broad interests>. Please don't hit me with any Holy Words or whatever. "

So much this. Except that for the sake of being a cleric of the god of secrets, pretend to be a cleric of a different evil deity.
The main weakness of good is that it's a reactive force by nature, presuming innocent until proven guilty and all that. Preemptive strike of that cleric "just because he admitted being evil" stops being good as soon as you come clean and show signs of cooperation.

[Acacia OnnaStik]

Just come clean. You can't keep it secret forever... Don't even try.

I think maybe the challenge of keeping the secret is part of the point, though? It's certainly what I'd be looking for if I were to play a character like this.

And there's a bit of a gap, for the Good PCs, between "you have a point about this task of ours helping both our causes, I won't try to stop you from contributing" and "I will actively help you keep your evilness a secret from others".

[JusticeZero]

Keeping that secret is foolish and basically an invitation for PVP. If the party discovers the secret it is going to be at a bad time and they are likely to be hostile. Just come clean with your team, save the secrecy for the NPCs.

[Tragak]

Hence the player keeping it secret from the other players is a bad idea (that has already been disregarded by said player as "not going to happen"). That doesn't mean that the character has to keep it secret from the other characters.