More like a goth teenage lich stage.Just a quick reminder. this isn't Vecna The God stats. It is explicitly Vecna The Arch Lich stats.
Sure, but how do you type the infinity symbol?
I already did that for you: Vecna the Archlich (standard, CR 26)I would probably just take the recently released Vecna and replace his spellcasting with the slots and spells of a 20th level wizard. He'd still have his various actions, bonus actions, and reactions in his stat block, maybe I'd add the extra line for flight of the damned which says "Vecna can use a spell slot of 6th level or higher to cast this again if it hasn't recharged."
Even if I used the current version, I'd probably change up a lot of his spells anyway, it's what I do for every spellcaster.
Haha, yep, already seen itI already did that for you: Vecna the Archlich (standard, CR 26)
See while I feel slotless design makes sense for the "only there for one fight npcs", I would argue that a Big Bad spellcaster is not that. They are more like a super high level antagonist PC opposing the PCs all day long. They are not just about the one fight (even if that ends up being their whole appearance), they need to be ready to use magic even when they are offscreen to scry on the PCs, haunt their dreams, set traps, create pocket dimensions, etc. I think it's more fair (and probably more intuitive by the time you are running a game with high enough PCs to fight Vecna) to manage his spellcasting as you would that of a 20th level Wizard, with maybe some extra spell slots, rather than create sui generis spellcasting rules for him to be able to do what he needs to do.I am not a fan of "slots" for enemy spellcasters in fights. It is an over design, I think, since that guy only has 3 to 6 rounds anyway.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.