Leo

Leo is a Shadowhunter and Bo's ally.

Immortal Instruments
Leo's history is unknown. Leo is a demon hunter. He was sent to protect the daughter of Zion and Ava. Leo met Bo at the club where she was about to be kill by a demon. Revealing it was her. Leo saves her. Bo ran away. He followed her to her house. Leo reveals to Bo that he thinks she is the savior and the key to saving humanity from the evil Bael.