Warning: Wikipedia contains spoilers, but not in this stub article
Mandos is the usual name for the Vala originally called Námo (Judge). Námo was given this new name in honor of the Halls of Mandos, over which he presides, where Elves go after they are slain. His wife is Vairė the Weaver, and his brother is Lórien.
In the roguelike computer game ToME the Halls of Mandos are location of a preliminary lost soul nightmare mode for experienced players.