Though Delta is an Active stationed out of the Los Angeles dollhouse, I don't expect all Dollhouse characters to remember him or muns to take him as part of personal canon (he is a fandom OC, after all). If you'd like to have your character remember him, this is all of the relevant information; if you'd rather not, no worries!
A few notes:
Delta does not have perfect control over his imprints. Most of the time, the Benjamin imprint is in command; Benjamin is not a fighter, and he isn't programmed with a whole lot of useful skills, but he can control the other imprints.
There is no meta-Delta personality, as such, because of the suddenness of the composite event. He is no Alpha or Echo; there were no signs of growing awareness, before the accident. He will be unable to deal with imprints long-term without severe medical problems.