bit of background then, dont know if anyones interested but hey
First of all Illumians in the campaign exist as nomadic clans after the other human houses ejected them from the empire for continued use of magic which is viewed as evil by the empire due to its use by the goblins in the last war to nearly destroy humanity, so now they're landless.
So the two illumian characters are from a clan that was destroyed by raiders, could be human could be goblinoid, and have been raised by the dwarf. After a few years they left his company to try and find out more about their kind, one of them fully embracing his magical heritage and becoming a wizard. Now, following what they've learnt, they've decided to return to their foster father and take him with them to show him a life beyond the tunnels following in the footsteps of some of his ancestors (Dwarves are big on ancestor worship rather than a pantheonic faith). This leaves adventure options pretty open with the two illumians searching for information about their heritage and the dwarf adventuring for new experiences and perhaps to try and surpass some of the achievemnts of his ancestors and become a legend himself.
Not the most original of back histories but its workable. The question is how to tie a Gnome Corsair into the group
Fingers