Tyro is a half-Dothraki, half-Meereenese former pitfighter from Essos who currently serves as Master-at-Arms for House Tarly.
Upon arrival at Horn Hill, Tyro was made a guard at Bonifer's insistance, but he was slack and disrespectful in carrying out his duties. After a few particularly nasty incidents, where Tyro had tried to mount and breed with several terrified smallfolk, Lady Leonette Tarly had an encounter with him. After this, Tyro's attitude changed completely and he became a loyal vassal to House Tarly, eventualy being promoted to Master-at-Arms.
His respect and fear for Leonette Tarly are not dissimilar to the Dothraki's fear and respect for the Dosh khaleen. He is friends with Hycae, a whore from Lys gifted to Bonifer Tarly by Varyo Velaryon.