Raava

"'You contain within you a great spirit. An entity of Light stronger than most I have encountered.""A being of great power, and even greater capacity for good. If it were a different shape I would swear it to be an angel.' (Shazam, Off To See the Wizard)"

Raava is a Spirit of Light originating from Earth 21. She fused with the spirit of a man named Wan, becoming the reincarnating Avatar Spirit. Every generation, she moves to a newborn human host and grants them the power of Bending to protect the world from the forces of Darkness.

Relationships
Vaatu

Wan

Korra

Xavier Bronze's SI

Zhi Hou

See Also:
Raava, on Avatar Wiki

Avatar, on Avatar Wiki