Asterios

A monster (hero) bestowed with the name of Lightning, but he was almost never called by that name. His alias that was widely spread all over the world is Minotauros, which means the "Bull of King Minos".

In Fate/Grand Order: Asterios acts as Euryale's protector, having constructed a Labyrinth as well as a Bounded Field around the island they're on to protect her.

In Fate/Grand Order Cosmos in the Lostbelt: Compared to the much more peaceful Asterios, The Lostbelt version of Minotauros is simply a monster that eats people who tread into the Labyrinth.