Azelf

Physiology
Azelf is a small, gray, fairy-like Pokémon. It has two tails that each have a red jewel on them. These are, presumably, two of the jewels which complement the Red Chain. Azelf has a partially cyan face with another red gem encrusted into its forehead. Azelf has a cone-shaped head with fins on the side that somewhat resembles a crown.

Gender differences
Azelf is genderless, although it is referred to as a male in Pokémon Mystery Dungeon 2.

Pokédex Entry
Diamond: Known as The Being of Willpower. It sleeps at the bottom of a lake to keep the world in balance. Pearl: It is thought that Uxie, Mesprit and Azelf all came from the same egg.

Behavior
Azelf has the ability to control one's will, according to the Sinnoh Pokémon Handbook. It can also enter the body of another Pokémon or a human. According to legend, it can cause humans to lose all will inside of them, making them completely immobile.

Habitat
Azelf sleeps beneath Lake Valor.