Zamatsu is a 36 year old Sith with Jedi Knight level training. Having gone by many names threw out his life "Abaddon The Destroyer", .
During his time as a padawan on Dantooine he encountered an ancient ancestor of Oodeef Mannamanna, who used Oodeef by means in contacting with him having been dubbed her protector, over time he acted on his instincts to keep her safe. The crystal he wears, he uses a guide that will bring him back to her every time, to ensure her safety, Cadara Ka'Taramas knew Oodeef was special during his time as her padawan.
"To fall is to break The Promise"
— Cadara Ka'Taramas/Xavious Lang
The Promase Broken
"Hammer into the heart Everything falls apart Hammer into the heart Beating on a broken promise"
— Miracle Of Sound
The Birth Of Zamatsu