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.
You can also see chain Angainor too. It was constructed by the Vala Aulë and held Melkor for three ages. In this drawing, Mandos holds angainor and coming for...well you know for who...!
and I guess He is happy about it.