Be the villain?

[MiuKujo]

I'm a relatively new DM and my party just wrapped up a relatively run-of-the-mill campaign. Adventurers get strong and beat up BBEG before he can do bad thing. We were talking about it after, and based on some of their more...questionable actions they decided the next game we run they want to be the bad guy. Start small and build up to being awesome OP BBEG doing bad things. My issue is this; I have no idea how to plan for that.
Knowing these guys, they'll start small. Breaking into shops strongboxes, killing witnesses, stuff like that. But, as all campaigns do, someone'll eventually sick an adventuring party on them. Whom they will promptly wipe out as the main characters are want to do. So all I see is this slowly raising the bounty on their heads, killing more adventuring parties, taking their loot (which they have nowhere to pawn off) and subsequently getting offed by an adventuring party that's stronger than them.
This can also lead to the campaign being rather episodic and repetitive. Seeing as they're the evil people, I would like for them to go out and plot their own warpath rather than me just handing quests out. So what could I do, as DM, to make sure they don't just get overambitious and squished, but keep the pressure on in a way that doesn't end with them having 20+ sets of +1 Full Plate.

[SirNMN]

I'm a relatively new DM and my party just wrapped up a relatively run-of-the-mill campaign. Adventurers get strong and beat up BBEG before he can do bad thing. We were talking about it after, and based on some of their more...questionable actions they decided the next game we run they want to be the bad guy. Start small and build up to being awesome OP BBEG doing bad things. My issue is this; I have no idea how to plan for that.
Knowing these guys, they'll start small. Breaking into shops strongboxes, killing witnesses, stuff like that. But, as all campaigns do, someone'll eventually sick an adventuring party on them. Whom they will promptly wipe out as the main characters are want to do. So all I see is this slowly raising the bounty on their heads, killing more adventuring parties, taking their loot (which they have nowhere to pawn off) and subsequently getting offed by an adventuring party that's stronger than them.
This can also lead to the campaign being rather episodic and repetitive. Seeing as they're the evil people, I would like for them to go out and plot their own warpath rather than me just handing quests out. So what could I do, as DM, to make sure they don't just get overambitious and squished, but keep the pressure on in a way that doesn't end with them having 20+ sets of +1 Full Plate.

let them start as just that once they get a good sized bounty, and corresponding reputation. Have BBEG wanna be offer them a job if they refuse but the squeeze one them with some bad guys who don't go after them, that a good way to get killed, they go after there stuff. They will either give in to get inside and take him down or go right for the kill on him. Then you mix it up he/ she is a puppet so no matter what happens it doesn't matter. If they join up have the #2 attempt to seduce one of them for support to off the boss also in the dark that the #3 is really in charge. They kill the guy the kingdom offer them a pardon if the will server as a brute squad for things like this. mean while #2 gets thing back in motion. how does that sound?
Also when they face a large group of mooks for the second time mix things, the low levels have vials of alcimist fire you miss you still do damage, or group is archers that fire vollys that doesn't need to hit the ac it does damage any how. give them good one shoot items those hurt even if the party is plenty stronger or multiple attacks the same day if they blow there strongest stuff first then the pack of 8 level 1 warriors was just to draw out there fire it the 4 level six rangers that will kill them. If you need more PM me

[TheifofZ]

Give them a goal to struggle for, same as if they were heroes.
A villainous goal, though, should conform more to their immediate desires and emotions, rather than more elaborate or good-hearted things.
They have to do some digging, or mug the right people, but they could find out about small towns ripe for the enslaving or groups of that one species they really really hate fresh for the slaughter.
Give them a hero they can't beat yet. Someone to hate that beats them down time and again, and rubs it in their faces. Every time they do something remotely villainous, have him come through and beat them down, but let them get away. Either he won't kill, or he brags or whatever.
Keep giving them bigger better things to get, and be sure to let them succeed sometimes. Mr. Hero can't be on duty 24/7. And he's human, he makes mistakes.
And then they finally get bigger than him and ohhhh, the satisfaction. And that's mid-game. After that, you want to toss them into the deep end. Figure out what motivates them as a whole, and then come up with something that is the be-all end-all of that. Wealth, power, destruction, pleasure, whatever.
But make it so they have to do the villainous quest thing to get the Mcguffin-o-doom.
and then... let them win. Let them glory in being the baddest mothers sons this side of the abyss. If they didn't kill everyone and/or destroy everything, then their great evil will surely draw young and rebellious heroes like moths to a flame. So that's a great lead up into a second campaign in the same timeline.

[Andezzar]

You should also give them a motivation to work together. Especially with PCs that have evil on their character sheet, the players often think they should commit evil deeds against their team mates. While this is not wholly unrealistic, it does not make DMing a campaign easier.

A few ways to achieve this is either by OOC agreement, or by IC backgrounds or by making the PCs part of a (lawful) evil organization that does not tolerate too antagonistic behavior between its members.

I think, even moreso than in a good party, you should take care that each PC can contribute to the story and that none of the PCs can deal with all problems. That too promotes cooperation.

[Baldin]

There is a very good campaign book made for pathfinder that has the PC's playing the bad guys. Look up Ways of the wicked, maybe you can get some inspiration from the books.

[SirNMN]

Give them a goal to struggle for, same as if they were heroes.
A villainous goal, though, should conform more to their immediate desires and emotions, rather than more elaborate or good-hearted things.
They have to do some digging, or mug the right people, but they could find out about small towns ripe for the enslaving or groups of that one species they really really hate fresh for the slaughter.
Give them a hero they can't beat yet. Someone to hate that beats them down time and again, and rubs it in their faces. Every time they do something remotely villainous, have him come through and beat them down, but let them get away. Either he won't kill, or he brags or whatever.
Keep giving them bigger better things to get, and be sure to let them succeed sometimes. Mr. Hero can't be on duty 24/7. And he's human, he makes mistakes.
And then they finally get bigger than him and ohhhh, the satisfaction. And that's mid-game. After that, you want to toss them into the deep end. Figure out what motivates them as a whole, and then come up with something that is the be-all end-all of that. Wealth, power, destruction, pleasure, whatever.
But make it so they have to do the villainous quest thing to get the Mcguffin-o-doom.
and then... let them win. Let them glory in being the baddest mothers sons this side of the abyss. If they didn't kill everyone and/or destroy everything, then their great evil will surely draw young and rebellious heroes like moths to a flame. So that's a great lead up into a second campaign in the same timeline.

that sound like fun collect there character sheets and bam pre generated bad guy

[NichG]

Evil tends to be more proactive than good. You can capitalize on that to design the campaign. Make the method you use to determine the resistance the PCs face explicitly known to them, and let them factor that into their plans. Furthermore, make advancement not depend on the power of the enemy they defeat, but rather have it be based solely on how far along they manage to get with their personal goals. That means that fighting that high level adventuring party isn't a source of free loot and XPs, it's actually a resource drain.

What I'd do is something like give the players a map of the various factions in the world at the start, along with an 'awareness meter' for each faction. I'd tell them that anything they try to do will have them come up against the intrinsic forces of that area, which have some particular character level. However, a faction that is aware of them and is hostile to them may replace those defenses with its own representatives up to a limit set by the faction's current power level and their current awareness rating. Actions that negatively affect a given faction will increase that faction's awareness meter. Very little can be done to make an awareness meter go down. (Incidentally, I'm stealing this mechanic from AI War).

The resources available to the PCs are entirely determined by the lands/locations/groups that they have brought under their dominion - they do not gain anything just from randomly killing a party of heroes. That is to say, the rewards are fixed, but the level can vary based on how sloppy they are. As the villains, the PCs gain an additional advantage - during character creation, they should outline their goals, and no matter how crazy or wild or nonsensical those goals are, the DM must place some thing or things in the world which are lynchpins for those goals, and the DM must always inform the player of the next such lynchpin directly.

Something like that could work, I think.

[Telonius]

Think of this just like a regular campaign. The only difference is that your character are willing to do a lot more hurtful things to accomplish their goals. There are always going to be more powerful characters than the party, whether they're Good or Evil. Becoming strong on either side will get you "noticed." Even if the characters are Good, if they start hunting devils left and right, somebody up the chain is eventually going to send a Pit Fiend after them, and there's just as much of a chance for it to become repetitive and episodic if they don't have a larger goal. (Some people like games like that; that's okay too).

But some attention is going to be helpful. So let's say they're starting to break into strongboxes. Maybe a local crime lord notices and decides to recruit the talent. Or if they're starting to kill, maybe an ambitious prince hires them to assassinate his older siblings. Nothing says all the "quest-givers" have to be nice guys.

[Quertus]

So all I see is this slowly raising the bounty on their heads, killing more adventuring parties, taking their loot (which they have nowhere to pawn off) and subsequently getting offed by an adventuring party that's stronger than them.

So what could I do, as DM, to make sure they don't just get overambitious and squished, but keep the pressure on in a way that doesn't end with them having 20+ sets of +1 Full Plate.

If you're looking to keep the Magic Item Wal-Mart feel, have an evil wizard NPC - perhaps even a shopkeeper from their last game - become their patron, buy their loot, build them items, etc.

If you're more concerned about helping to steer the PCs, said patron could also send them on quests for dangerous artifacts, to kill tribes (of good or evil creatures, perhaps including some from their previous campaign) that are in the way, or even to assassinate npc adventurer parties.

Or, if you want them to be proactive, have them and the evil wizard patron start / end up in a more isolated locale, where there aren't be a lot of adventuring parties to come and crush them.

[daremetoidareyo]

Take a moment and Google "tale of an industrious rogue" or look on the general role-playing forum here for kavemans "cattle driving necromancers" for some evil play examples.