No, the group has a bad history with the derro vamp with mutual serious grudges, so after irritating them incessantly for a couple months with this guy I need to give them some closure while furthering the main campaign thread. I did consider putting Gorakhan into the arena to fight alongside him, but I was concerned that 2 vampires might be a bit much to handle in a single fight. Gorakhan will just have to keep until they party offends the Thane in some way (high probability).
The arena will be stocked with a group of npcs culled from previous enemies the party failed to utterly destroy; an erinyes ranger from a cult of devil-worshippers the party pummeled and then basically ignored (low wisdom), a mutant sahuagin skum gladiator with grafts (created using that handy skum template from CW, btw! Nice!) sent by a cabal of aboleths the party stole from (outright foolish!), a death knight of Orcus (even Orcus hates grave-robbers), and so on. Once the party gives me the final roster of characters I'll crunch some numbers and see if I can squeeze someone else in there. Gorakhan is definitely
on the list.
So far we're still working out the conversion of items and skills. In the last game though they were hit by a very large (15hd) rust monster, so that should simplify the item side of things.
I think everyone is psyched about the conversion; each character is getting something that they didn't have before in the way of abilities, and that overrides concerns about item slots or how the skills all knit together. The hard part comes down on me since I have a backlog of npcs to convert!
P.S. the derro's name is Harry Palmer. He had five sisters, but they were all killed by the party. He's a cleric of Manos, the Hands of Fate. See what I mean about closure?