The Master of Masters

The Unknown is a hooded character introduced in Kingdom Hearts χ. The Unknown's true identity and purpose remain unknown.

Kingdom Hearts χ
After helping Chirishii fend off the Minute Bombs in Daybreak Town, the player goes to sleep. He or she has a dream, in which the five Foretellers converse with the Unknown. Before the player has a chance to approach the Foretellers and their mysterious visitor, he or she is engulfed in darkness and wakes up.

Appearance
The Unknown appears as a person completely concealed in a black coat. Nothing else is known about the unknown's appearance beneath the hood.