Really cool idea! A few little things. A bit of telegraphing where Vanclair will teleport to would help and also reducing the nameplate cooldown at the start of fights would feel less punishing for dying. I think a half second immortality against future hits would make the fight feel easier, or at least some more knock back. A couple of times I died because I sort of got stuck in the path of his attacks and took 2 or 3 hits in one attack. The artwork is superb and the music really fits with the aesthetic.