FusionDex

According to legend, Jirein can grant the wish of a pure-hearted human, but only when the eye on its belly is fully open. When it isn't sleeping, it rescues humans and Pokémon that have fallen into the icy waters where it lives.

To protect its herd, the leader battles anything that invades its territory, even at the cost of its life. Jirein is said to make wishes come true.