Ossë is a
Maia in service to the
Vala of Water,
Ulmo in
J.R.R. Tolkien's mythology. He is the Lord of Storms & Coasts, and is usually mentioned in the same breath has his wife, the Maia
Uinen, Lady of the Seas.
Ossë's portfolio is the shallows, the inlets, the coastal shoals. He especially enjoys a good storm, with the wind whipping the waves. Uinen holds portfolio over all salt water and the creatures therein, and calms Ossë's excesses.
During the making of Arda, Ossë defected to Melkor and his waves nearly destroyed Middle-Earth. But through the love of Uinen, he was brought back into the fold. For this reason, Uinen was especially loved by the mariners of Numenor.
Ossë loved the Quendi, and taught the Teleri many skills of "sea-lore and sea-music." He convinced many to tarry, either on the shores of Middle-Earth or on Tol Eressëa.
After the First Kinslaying, Ossë was not allowed to sink the stolen Swan Ships of the Teleri. However, Manwë and Ulmo forgot about Uinen, and her tears raised a storm powerful enough to capsize many.
During the War of the Silmarils, Ossë and Uinen gathered information for their boss, Ulmo, who passed it along to the Noldor. At the war's end, Ossë raised the island of Andor for the Edain, on which the founded Numenor.