The lich is classic monster in Dungeons and Dragons. There are several famous Liches in D&D lore: Szass Tame, Acererak, Vecna. Here’s the stat block from the Basic Rules:
I find the lich to be a bit tricky to use. They are a glass cannon. Three of their best spells can instantly kill a player, making it a little hard to pull your punches. Here are some tips for running a lich without getting rolled by your players, or TPK’ing them.
Throw Your Instant Death Spells Early
Disintigrate reduces the body of a creature killed by it to ash. Finger of death kills them and turns them into a zombie under the control of the caster. Taking a player out with either of these spells puts them out of the game pretty much permanently. Power word kill is scary, but at least it leaves a body. Because of this, consider casting disintegrate and finger of death early in the match, where you can count on them doing a lot of damage but not vaporizing a player. You might also want to encourage your players to make some relationships with temples where they can find someone to revive a dead PC, or unzombify them as needed.
Make the Most of Cloudkill
Cloudkill isn’t just for choking your enemies to death. It creates full obscurement, which gives a creature in it full cover. Combined with a Lich’s immunity to poison damage, this gives your lich a mobile bit of cover they can hide in. The cloud moves away from you 10 feet on each turn, so with carful positioning inside the cloud you can control how it moves.
A Lich Can Always Make New Friends
The animate dead spell only creates one skeleton or zombie per casting. You can up level for an additional 2 undead per spell level. They would have to recast ever 24 hours in order to maintain their minions. I would assume that any lich worth their salt would have some undead servants on hand to hold their grimoire gather mortals to experiment upon. So, your basic lich can maintain a coterie of 13 undead friends with their 9th level spell slot. This is also a good way to make sure you don’t have that spell slot lying around to cast power word kill with. Who needs the temptation? If you’d rather keep it though, you can burn all three of your 3rd level spell slots every day to keep 12 undead animate.
Now that you’ve looked at the basic lich, take a look at the stat block I put together for Szass Tam.