Thorax

As all changelings, Thorax doesn't eat: rather, he is forced to feed on the love of other creatures, essentially draining them of all warmth towards others. It is said that to be drained of love is worse than death, because it turns you into a shell, so changelings "take pity" on their victims by slaying them after feeding. However, Thorax could never clear his conscious of what he was doing, and ended up putting himself on a "diet:" basically starving himself. It's only when an older human named Garlen sacrifices his own love for Thorax that he learns there's another way to survive— without hurting himself or others.