Dheyn actually caused me a little trouble to begin with. I knew I wanted a xenology specialist onboard (handy thing to have when facing totally new and unknown races), and I knew that he was to be an alien but wasn't sure just what kind.
He started off as a Deltan but that didn't feel right, so I asked for suggestions on another site and someone threw out Thallonian. Amongst all the others it just stood out to me as something different that I hadn't used before. Also a bald, 2.1 meter, scarlet-skinned man is going to stand out in the crowd.
About to start work on the next couple of little intros, hopefully get them posted tomorrow.