D&D 5E Vs Vecna battle simulations.

[MarkB]

I ran the numbers. His chance of escaping a double-grapple is about 1% if you roll once vs. both grapples and half that if he has to roll separately against both.

Even if he manages to escape, Leon has Sentinel---so when he tries to leave the field Leon has a good chance to stop him by reducing speed to 0.

True, but his shortest route out of the field doesn't take him out of Leon's reach (though that could change), and once he's out he'll teleport.

Talking of which, Sentinel would have allowed Leon to attack Vecna when he attacked Egar, with little downside as he'd have got his reaction back next turn.

 

[MonsterEnvy]

Should note the Necrotic Damage comes from Vecna using the dagger, it’s stated to be a +2 dagger when anyone else uses it, so the Necrotic damage comes from Vecna himself.

 

[FitzTheRuke]

Thinking about the anti-magic field - I think if this was one of my home games, I'd have had Vecna turn into a pile of bones in it. Then as the party is celebrating the easy victory, as soon as the spell ends, have him pop back up again. It might work as a delay, but not THIS much of a delay.

 

[FitzTheRuke]

Should note the Necrotic Damage comes from Vecna using the dagger, it’s stated to be a +2 dagger when anyone else uses it, so the Necrotic damage comes from Vecna himself.

Yeah, I see that as part of his undead nature, like a wight's grasp, that he can channel through the dagger, not a property of the dagger itself.

 

[DND_Reborn]

Should note the Necrotic Damage comes from Vecna using the dagger, it’s stated to be a +2 dagger when anyone else uses it, so the Necrotic damage comes from Vecna himself.

Yeah, I see that as part of his undead nature, like a wight's grasp, that he can channel through the dagger, not a property of the dagger itself.

It is magic IMO, due to the highlighted statement, whether the magic is part of the magic of the dagger, or just part of Vecna's magic, especially since it is the same amount (2d8 necrotic damage) both on the hit and the rounds afterwards:

 

[DND_Reborn]

True, but his shortest route out of the field doesn't take him out of Leon's reach (though that could change), and once he's out he'll teleport.

True, he could move to the space above Leon, and one to the right (shared with the pillar). I suppose then Leon will have to move further into the circle to allow Sentinel to work.

Talking of which, Sentinel would have allowed Leon to attack Vecna when he attacked Egar, with little downside as he'd have got his reaction back next turn.

Excellent point! I forgot about that and will add it to Vecna's Turn above as an update.

Update: He ended up missing anyway...

 

[Stalker0]

I feel like this fight is effectively over, even if Vecna does manage the incredibly difficult task of escaping, I mean he's getting pincushioned, and the party is doing just fine. I think this has effectively shown that a 20th level party will take Vecna to school (which I think most people were expecting, 20th level is just insanely powerful).
So I say now that we have some rulings in place, and everyone has a feel for the characters, that you reset and do it again at like 16th level.

Much more interesting than spending 2 days of posting on watching torch damage.

Also on the escape attempt versus multiple grapplers, I do the rolls one at a time, and each success means you break out of that grapple (and the enemy has to regrapple). This gives a better overall success chance, if they have to beat every single grappler at once, they just have almost no chance.

If you really want to keep playing it out, then I would assume all of the PCs just have whatever gear they want mundane wise. Lets be honest, if they have no magic items, then they have gobs and gobs of gold, realistically there is 0 reason going into a monster cave that they would not be packed with every single mundane item they can get their hands on.
Firebombs, flaks of acid and oil, thunderstones, whatever. If its mundane and it does damage, I would just assume they have it. Its 20th level for Pete's sake!!!!

 

[DND_Reborn]

I feel like this fight is effectively over, even if Vecna does manage the incredibly difficult task of escaping, I mean he's getting pincushioned, and the party is doing just fine.

Much more interesting than spending 2 days of posting on watching torch damage.

If @FitzTheRuke and @Smythe the Bard agree, I can run the scenario out as follows:

Leon is IDS twice each round, moving into a better position so Sentinel will activate IF he escapes.
Malek is lighting torches and passing them out.
Hjalman will burn him with a torch twice each round.
Egar moves out of reach to prevent Vecna from striking him.

And as a thought, someone could disarm Vecna, taking the dagger away from him (fairly easily in all likelihood...) as well LOL.

 

[MarkB]

I feel like this fight is effectively over, even if Vecna does manage the incredibly difficult task of escaping, I mean he's getting pincushioned, and the party is doing just fine. I think this has effectively shown that a 20th level party will take Vecna to school (which I think most people were expecting, 20th level is just insanely powerful).
So I say now that we have some rulings in place, and everyone has a feel for the characters, that you reset and do it again at like 16th level.

Much more interesting than spending 2 days of posting on watching torch damage.

True. I was thinking it's worth going through a few turns in shorthand mode just in case he gets clear and manages to fire off some abilities, but I hadn't run the math on the chances of him managing to do so. It's probably just as easy to call it at this point.

Also on the escape attempt versus multiple grapplers, I generally use the "Rule of Cool" on this one, allow one character to bust out of multiple grapples all at once, assuming their check beats all opposed grapple checks. This mirrors the "super strong hero breaks out of the pile of guys in one super move", and I think is just plain cooler than "roll against this guy, now roll against that guy".

If you really want to keep playing it out, then I would assume all of the PCs just have whatever gear they want mundane wise. Lets be honest, if they have no magic items, then they have gobs and gobs of gold, realistically there is 0 reason going into a monster cave that they would not be packed with every single mundane item they can get their hands on.
Firebombs, flaks of acid and oil, thunderstones, whatever. If its mundane and it does damage, I would just assume they have it. Its 20th level for Pete's sake!!!!

Yeah, I'm not sure whether that was the intent with the previous discussion, but while I'm fine with it requiring two rolls to break out of a double-grapple, I agree that it should only require one action.

 

[Flamestrike]

His math is not off (you can't just declare math is off without showing the math is off) and he's not white rooming it he's using the room Vecna is in for the adventure and the tactics WOTC published in their Vecna video! Nor does Vecna get a turn to teleport, he's dead. But even if he did, the tactics WOTC state in the video is that he doesn't do that.

Vevna can teleport as a reaction to being hit. Behind full cover.

So Fighter 1 has his turn, and Vecna teleports after getting hit with arrow 1. The rest miss (they didnt take seeking arrow). Rinse and repeat for Fighter 2.

His DPR calculations had him using lucky to grant 3 extra hits, and he didnt divide his special arrow DPR by his hit probability and he factored in all damage with his crit DPR (and not just dice).