In Lincoln in the Bardo, who was Roger Bevins III?

Roger Bevins III, along with Hans Vollman and the Reverend Everly Thomas, work together to convince the spirit of Willie Lincoln to leave the Bardo. Bevins is sympathetic toward the distressed Willie and his devastated father. He even inhabits Lincoln's body in order to will the man away from visiting the boy's grave.
Before entering the Bardo, Roger Bevins III committed suicide by slitting his wrists with a butcher knife. He had been heartbroken after his lover, Gilbert, had ended their homosexual affair, which was deemed unacceptable by society. Roger Bevins III ended up in the Bardo because right after slitting his wrists, he realized that life is a beautiful gift that should not be wasted.
In the story, many of the spirits are preoccupied with the circumstances surrounding their deaths. In this case, Bevins thinks he is still lying in a pool of his own blood waiting to be found and believes he is still alive for most of the novel. His new-found appreciation for life shortly before his death is reflected in his poetic phrases about the sensuously beautiful world, which causes his body parts to comically multiply.