The human captain is the highest ranking field commander of the Wing Guard and one of the few working against the rampant corruption among its ranks.
As a junior officer, Selis worked against the corruption in the Wing Guard to little avail. He was kept in the lowest ranks and given the most meaningless assignments. Somehow, Selis still kept his idealism and morale intact for years before Calrissian began making his changes, and since the corruption around him has been significantly pruned, his star has risen within the guard. He currently holds the rank of captain, the highest rank still afforded the opportunity for regular work in the field, and has declined further promotion on two occasions keep that right.