Midir, also known as Midhir, is the son of the leader of the Tuatha Dé Danann, Dagda. After their defeat, he would eventually move and live in the sidh of Brí Léith. He is one of the leading characters in saga "The Wooing of Étaín."
He was married to Fuamnach when he fell in love with Etain. Eventually, he would lose her; she would then be reborn and eventually become married to the high king of Ireland of that time. Midir would attempt to win Etain back and would either succeed or fail depending on the version.
A servant of the angels overseeing the construction site that connects the Expanse to Harajuku. He appears before Masaki and gloats of his greatness before attacking him. After losing he goes with Plan B, cursing Shou Ougi with the Dark Slumber and warning that everyone he knows will know turn on him. Midir then vanishes. Later he can be fought as a regular encounter.