A lot, actually. Shinigami are Souls that possess sufficient spiritual power, entered the Shinigami academy, recieved an Asauchi which they can imprint upon to turn it into their personal Zanpakuto became members (soldiers) of the Gotei 13 and who's assigned job is to purify Hollows, transport Souls and generally keep the afterlife safe. Aside from their signature Zanpakuto, Shinigami can also use Kido spells. They also tend to dress in black.