He's a god, dear friend. Don't expect for him to have a middle and last name. Poseidon's real name is indeed Poseidon. He also goes by God of the Sea and Neptune, his Roman counterpart.
Neptune
Rhea.
It does not have a known name apart from 'trident'.
the function of Poseidons temple was for Poseidons honor.
He had no last known location because he was not real. Even if he were, he was a god, and thus, omnipresent.
Rhea.
cronus
Cronus and Rhea
Triton
a trident
some nick names for poseidon is neptune and poseidon is a greek god and neptune is a real roman god of the sea like poseidon and poseidons coulture is neptune but poseidon is much stronger and much heard from people then neptune is and poseidons planet is neptune and thats why its so cold
He doesn't had friends