Kell Tainer is a human male pilot and demolitions specialist, one of the founding members of Wraith Squadron in Aaron Allston’s X-Wing: Wraith Squadron (Bantam Spectra, 1998).
He belongs to the unit for the reason everyone in it does. Wraith Squadron — briefly Gray Squadron — was assembled by Wedge Antilles in 7.5 ABY out of pilots on the verge of discharge, deliberately built from washouts and misfits, because a hybrid starfighter-and-commando outfit needs people with useful skills more than it needs conventionally excellent aviators. Tainer can fly and he can bring a building down, and the second qualification is why he is there.
Allston’s trick throughout the Wraith books is to make the misfit premise carry real weight rather than sit as a joke: every member of the squadron is in it because something went wrong, and the novels take those somethings seriously. Tainer’s are family, inheritance and a very specific fear he has to fly through repeatedly.
He is Star Wars Legends, and his homeworld is left blank here rather than guessed.