CapnZapp
Legend
This is a good thing.5E is very much a hit point attrition game. The primary defense is hit points. AC, saves, and every other type of defense can be circumvented by hit points.
Tell me your hit points and I tell you your level. Or challenge rating, I guess, but... yech.
I'm amazed how the encounter guidelines never begin counting from the other direction.
How much damage can the party deal consistently per round, if they make an effort but doesn't burn everything? A hundred points, you say?
And you want the BBEG to last three rounds? Hmmm... I wonder how many hit points he should have...
130 hp you say? WRONG. How about... *drum roll* 300!
And then, if he's supposed to handle the party all on his own, you double that. If he's particularly front-loaded (like a lich admittedly is), AND he's smart enough to surround himself with non-trivial beasties, you can shave some off. But not too much.
130 hp? Then there's no point casting "smart" spells that debuff him. The entire concept of making him save or suck is devalued. In the immortal words of Treantmonk, perhaps just deal 130 points of damage.
To me, it's blindingly obvious this is a much more practical approach to BBEGery than the simulationist approach "okay so he's eighteenth level, so this gives him 18d8, but that only gives him 81 hp so we need to tweak his Con, and then this and that spell...."
Simply give your BBEGs triple the damage output of the party and... done.
Of course, this means DMs have to know their parties and that's difficult so we can't have that. Better to create a freakishly complicated yet-laughably-inaccurate encounter framework to give off the illusion the game is simple! Yay!
