Manannán mac Lir (Manannán mac Lir)
God of the sea, keeper of the otherworld, and the reason the Isle of Man has its name.
Manannán mac Lir is the sea itself as much as a god of it. Waves are his horses, the ocean is a plain he rides across, and fog is his doing. He owns a boat that goes where its owner wishes without sail or oar, a horse that runs on water, and a cloak that he shakes between two lovers so that they never meet again.
He belongs to the Tuatha Dé but stands slightly apart from them, more often a visitor than a resident. After the Milesians took Ireland and the Tuatha Dé went into the mounds, it is Manannán who is credited with raising the féth fíada, the mist that hides them from human sight, and with giving them the feast that keeps them from ageing.
He rules the otherworld, variously named Eamhain Abhlach or Tír Tairngire, the land of promise, and he moves between it and Ireland freely. In the voyage tales, the immrama, a crew far out at sea will meet him riding the other way across what they take to be water and he takes to be a flowering plain.
The Isle of Man is named for him, or he for it, depending on who is telling it. Manx tradition keeps him as a first ruler of the island, and bundles of rushes were left for him there as rent well into recorded memory.