Heaven is a doctor that lives on Denchar in Xebec’s Demise.
Though Karr attempted to make contact with Heaven before leaving Xebec’s Demise, the neighbors reported Heaven as having been killed. No body was seen, however, so there is still some chance that Heaven is still alive.
Apparently Heaven escaped death during the troubles of Denchar, as he was among those rescued by the crew. He departed the crew’s company upon arrival at Citadel.