Matthew
A troubled human that was resurrected as a Raven, the companion to Morpheus, the lord of dreams.
Where is he from?
While Matthew, as he is depicted in GND, is the talking Raven companion to Morpheus in the pages of Neil Gaiman comic opus The Sandman, the character has a pretty convoluted comic book history. He started out as a recurring character in the pages of Swamp Thing, also occasionally showing up in Doom Patrol, before his powers lead to him becoming an abusive addict. He was taken out of the story in the first issue of Alan Moore's seminal run on Swamp Thing (my personal favorite comic of all time), and later was killed by Swamp Thing's archnemesis, Anton Arcane, and resurected to become a Raven in the pages of my OTHER favorite comic of all time. Comics can be insane sometimes. I cover a lot of this stuff over on my other website, the DC Continuity Project.
Comic Appearances
GND 187 - Sarah, Christine & Luna see off Susan Sto Helit. She talks to her grandfather Death (and his horse Binky), who talks to Death of the Endless, who talks to her brother Morpheus, who then takes the Pale Man to the Nightmare Realms, where he can befriend the Corinthian & Matthew.