Medulla Crystal
Crystal Information

The Medulla Crystal is a very powerful crystal that serves as a second brain to the user. It is used with the Suit of Untold Vengeance since its controls were too complex for the human brain itself. But using it made the user go crazy. It was supposed to be destroyed so no one could use the suit, but the Dark Ace somehow got his hands on it; the sky knight Aerrow managed to destroy the crystal permanently.[1]