Maralith
After making our way back to the original room, I wander up to the red orb, and we're dropped into the fight with Maralith. It may be because I'm tired, but I just set up an autobattle and keep an eye on it - Glitz with his Flares - Clair laying down Healagas, and the other two going in for the big physical attacks.
It's far far from the most dramatic fight, but with this setup's regeneration via Clair’s Healagas, it just becomes a relatively short back and forth between us and her, and there's only ever going to be one winner. She dissolves again and we're free to head further downstairs.
I don't know whether Maralith or Lich kept their original stats, but if they did, it's a nice way to show how far we've come from the rubes who turned up at Castle Cornelia all of those posts ago, with 4 Crystals and pretty much nothing else...