Question about rogue/fighter multi class

[dtuned]

Ok, so I've been playing this class for a while now, currently I am 5 rogue 5 fighter and the damage output seems crazy op to me. I mean, considering how much damage the rest of my group does. So I just want to share how much damage I'm doing and how I'm doing it and you guys can proceed to call me an idiot because I have to be wrong lol. Ok here we go

Level 5 rogue/level 5 fighter.
If I get the jump on someone and surprise them, I get an instant crits on all my attacks and advantage
If after the surprise round, i beat their initiative and go first I also get crits and advantage. All of this due to assassinate feature.

I have 2 finesse weapons +2
Dragon sword +2 1d6
Tinderstrike +2 1d4 + 2d6 fire damage

Let's just take the d4 out of the equation so try and keep things add simple as we can

Now let's say I get the jump on everyone and surprise my target, I attack.

3d6 sneak attack per attack = 6d6 since I am two weapon fighting + 3d6 for my weapons,

So far we are at 9d6

Now I get an extra attack from fighter level 5 and tinderstrike is in my main hand so that's another 2d6 for the weapon and + 3d6 sneak attack damage

We are now at 14d6

NOW I will use action surge
Which states I can take an additional regular action and a bonus action which means I should be able to do all of that over again so we will double it

We are now at 28d6 with a total of 6 attacks, all of which are crits and have advantage so that's a minimum of 56 and a max of 336 and that is without adding the weapon bonuses and dex bonuses and crit. ALSO if after all that is done, I roll for init and go first, I get to do all of that again minus the action surge part, so that's another 14d6 on top of all that...

I also have the alert feat and +5 init so it's pretty hard to NOT go first

I don't think I left anything out, im sure I'm doing something wrong because that is waaayyy OP. Please let me know.

[clash]

Ok, so I've been playing this class for a while now, currently I am 5 rogue 5 fighter and the damage output seems crazy op to me. I mean, considering how much damage the rest of my group does. So I just want to share how much damage I'm doing and how I'm doing it and you guys can proceed to call me an idiot because I have to be wrong lol. Ok here we go

Level 5 rogue/level 5 fighter.
If I get the jump on someone and surprise them, I get an instant crits on all my attacks and advantage
If after the surprise round, i beat their initiative and go first I also get crits and advantage. All of this due to assassinate feature.

I have 2 finesse weapons +2
Dragon sword +2 1d6
Tinderstrike +2 1d4 + 2d6 fire damage

Let's just take the d4 out of the equation so try and keep things add simple as we can

Now let's say I get the jump on everyone and surprise my target, I attack.

3d6 sneak attack per attack = 6d6 since I am two weapon fighting + 3d6 for my weapons,

So far we are at 9d6

Now I get an extra attack from fighter level 5 and tinderstrike is in my main hand so that's another 2d6 for the weapon and + 3d6 sneak attack damage

We are now at 14d6

NOW I will use action surge
Which states I can take an additional regular action and a bonus action which means I should be able to do all of that over again so we will double it

We are now at 28d6 with a total of 6 attacks, all of which are crits and have advantage so that's a minimum of 56 and a max of 336 and that is without adding the weapon bonuses and dex bonuses and crit. ALSO if after all that is done, I roll for init and go first, I get to do all of that again minus the action surge part, so that's another 14d6 on top of all that...

I also have the alert feat and +5 init so it's pretty hard to NOT go first

I don't think I left anything out, im sure I'm doing something wrong because that is waaayyy OP. Please let me know.

There are a few problems with how you are playing. First and foremost sneak attack only applies once per turn. So you cant get sneak attack on your attack and your offhand attack and your extra attack. Second assassinate only grants crits against surprised creatures, so only in the surprise round. Thats only one round of auto crit, not 2. You get advantage both rounds before people that have had a turn but not auto-crit. Finally, action surge only grants an extra action not an extra bonus action. No matter how many actions you have access to you still only have one bonus action. Thats all the problems I see but should reduce your dmg to a reasonable amount.

[Grod_The_Giant]

Well, your first problem is that Sneak Attack is only one per turn, not on every attack like in 3.pf. So that's 15 dice gone right there. And Action Surge only gives another Action, not a Bonus- so that's another 2d6.

The last big contributor seems to be Tinderstrike, which is a magic item and thus not assumed in the game's basic math. If you start handing out items like that, DPR will naturally go through the roof. If we assume you had a normal sword, that's another 8d6 gone.

Your final routine, not including the incredibly powerful magic item, is five attacks plus 3d6 sneak attack, one per short rest. Which is very impressive! An Action-Surging Assassin is right up near the top of the charts when it comes to burst damage. But it is a burst, and your sustained damage, while nice, will ultimately be much lower.

[Christian]

Also, at the end of a surprised creature's turn, it is no longer surprised. Along with allowing it to take reactions, etc., that also means that assassin's attacks no longer automatically are critical hits when they hit. So to get that bonus, you not only have to surprise a creature, you also have to beat it on initiative. And even then, you'll only get it for the first round of attacks, not the second.

[Specter]

Situational, yes, but devastating in that situation. There's even a handbook dedicated to that combo, the True Assassin Handbook. You should check it out.

[James_the_Giant]

As mentioned Sneak Attack only once per turn, but if you'd like to push that damage further you could take a level of warlock to have access to Hex. Hex would take up your first bonus action but give you an addittional 1d6 on each successful hit(including any ranged options that you might use). With 5th lvl fighter dual wielding you get 3 attacks per round using your bonus action, or 2 per round without. That's an additional 2d6 on the first round, potentially, and 3d6 every round after the first. Then if you kill the target you can use your bonus action to move the Hex to another target.

Or you could find a way to be able to cast Haste on yourself, which is super power with Fighter's Multiattack.

[Corran]

snip
If you surprise someone AND you beat them on initiative, then you can attack them with advantage and if you hit them it is considered a critical hit.
If there is no surprise, you just have advantage against anyone who hasn't take a turn yet. If you hit them, it is NOT a critical.
Surprise or not, if you dont win initiative, you attack normaly with no benefit from the assassinate feature. Assassinating only provides bonuses for when up against a target against whom you won initiative.
You roll initiative before the surprise round takes place. During the surprise round, a surprise creature stills gets a turn, though they cant do anything up until and during that turn. After their turn ends, they are no longer surprised, and they cn even take reactions even during the surprise round, provided their turn passed and thus the surprise condition was ended.

Also, sneak attack is restricted as once per turn, meaning that no matter how many attacks you get to do during your turn, you can only add the sneak attack damage only to one attack, and thus deal it only once in your turn.

[Tanarii]

Several other people have explained how surprise works, but the key thing is: there is no surprise round in 5e.

There is only the first round of combat, in which surprised creatures remain surprised until their first turn comes up in the initiative order. They can't act on that turn, but they are no longer surprised.

Also, surprise can potentially be fairly hard to achieve, depending on how your party operates and how good they are at stealth (including the use of magic such as Pass without Trace). To be surprised, an enemy must fail to beat every single creature in your Party's Stealth check with its Passive Perception. So if you have one Party member with a low Stealth check (like someone with a low Dex in HA), it can be quite difficult to surprise your enemies at all.

Alternately you can be far enough from your party that you count as two groups, but then you risk defeat in detail.