lethe: all of the other underworld rivers (especially styx, who is important to charon, as well). nymphs. mnemosyne. any of eris' kids. hypnos! she runs through his cave! charon: likes jules, any chthonic gods. any of the heroes to enter and leave hades. any of nyx's kids. anteros: MOAR EROTES. nemesis: more siblings. more people who "aren't awful."