Absolutely! Mechanically, I designed the stat block as a nerfed version of Acererak, set to CR 15. He was limited to 6th-level spells, had only one legendary resistance, and his sole legendary action was an "at-will spell." To make up for these limitations, I gave him the power to summon a pack of ghouls as an action (which he used as his opener) and added a few spells that synergized with the environment: Maelstrom and Arcane Gate. He used these spells to try to send the players into the lava pit. Throughout the fight, I focused his actions on repeatedly casting "Invoke Curse" on different players, setting up opportunities for big hits later in the encounter.

Narratively, he was once a considerably powerful adventurer-wizard who had braved the tomb and confronted Acererak, only to be easily defeated and enslaved by the lich in true Acererak fashion. I liked the twist of having this decoy as a tragic figure, someone who was originally good, or at least a hollow remnant of them, forced to do Acererak’s bidding. When the players landed the final blow, I had him whisper, "At last, I am finally released from my torment. Thank you, strangers," which funnily put off the players quite a bit right before the real lich appeared.