Hmm... Well... I instinctively thought Nao, of course. If you don't want some skills to die out, certain NPCs would be useful to have around. Some like Ranald would be good, Trefor, (I'd say Malcolm but that's only because I like him), and then some elf NPCs like Castanea, and/or Atrata and then a couple giants like Meriel, Krug and/or Kirine. But... I just listed a lot... I think you should save some humans, some elves and some giants though. Just so that each race is supported by some elders.

My idea:

Human:
Trefor
Ranald

Elf:
Castanea
Atrata?
Hagel
(Granites would be cool. Just to see him grow cold and crazy. I can see it happening)

Giant:
Meriel
Krug or Kirine

I dunno, I listed a lot of characters. Sorry. D: I applied for the guild though. If I get in, I'll join the rp for sure.