For 10 points, name this brother of Hades and Zeus, the Greek god of the sea.
This deity was raised on Rhodes by Capheira and the Telchines. After raping a Lapith woman named Caenis, this god transformed her into the male warrior Caeneus. This god found Demeter hiding in a herd of mares and fathered the talking horse Arion with her. Iphimedia's affair with this god resulted in the birth of Otus and Ephialtes. Odysseus earned this god's enmity by killing Polyphemus, this god's son. This god is also the father of the merman Triton. For 10 points, name this brother of Hades and Zeus, the Greek god of the sea.
This deity was raised on Rhodes by Capheira and the Telchines.
Poseidon [accept Neptune until "Greek" is read]