Board Thread:Questions and Answers/@comment-28414362-20150325191838/@comment-10452902-20150601025320

All Shinigami and Plus reincarnate into the World of the Living normally unless certain special circumstances accrue such as being eaten by a Hollow which causes them to simple not exist or being eaten by a Bount which does the same thing. It's hard to tell if failing to be hollowfied results in a normal reincarnation or if the person simple ceases to exist though the latter seems more likely as they become sand/dust like Bounts do when they die. Normal Hollows go to the Soul Society when killed by a Shinigami as I believe Gillians do as well however, Arrancar do not but we don't know truly what happens to them though it has been suggested that they go to Hell. Whether or not Adjuchas and Vasto Lordes do as well is unfortunately unknown to us however, we do know that all Hollows killed by a Quincy cease to exist without exception. Quincy are much different, their very souls are connected to their king's so when they die, it goes to their King along with all their knowledge, experience and skills unless eaten by a Hollow. I say being eaten by a Hollow is an exception because I am rewatching the anime and I noticed one of the Arrancar who I believe dies said Quincy in their name.