Manannán mac Lir
Manannán or Manann, also known as Manannán mac Lir ('son of the Sea'), is a sea god, warrior, and king of the otherworld in Gaelic (Irish, Manx, and Scottish) mythology who is one of the Tuatha Dé Danann.
He is seen as a ruler and guardian of the otherworld, and his dominion is referred by such names as Emain Ablach (or Emhain Abhlach, 'Isle of Apple Trees'), Mag Mell ('Plain of Delights'), or Tír Tairngire ('Land of Promise'). He is described as over-king of the surviving Tuatha Dé after the advent of humans (Milesians), and uses the mist of invisibility (féth fíada) to cloak the whereabouts of his home as well as the sidhe dwellings of the others.
In modern tales, he is said to own a self-navigating boat named Sguaba Tuinne ('Wave-sweeper'), a horse Aonbharr which can course over water as well as land, and a deadly strength-sapping sword named Fragarach, though the list does not end there.
Manannán appears also in Scottish and Manx legend, where he is known as Manannan beg mac y Leir ('little Manannan, son of the Sea'). The Isle of Man (Mannin) is generally thought to be named after him, though some have said he is named after the island. He is cognate with the Welsh figure Manawydan fab Llŷr.