Cha Un-Su (チャ・ウンス, Cha Unsu) is the coach for Red Bison.
Cha has black hair with one grey streak at the front and has black eyes. He also wears glasses.
Cha seems to only care about winning since he gave orders that could injure Inazuma Japan's players that in the end happened to Gouenji. He also doesn't seem to care much about his own players since he didn't act when some players injured their own captain, Seok Min-Woo.
Cha Un-Su was talking with Baek Shi-Woo before the match started against Inazuma Japan while the other players were already on the field, telling him Japan and Korea were equal in skill and that the match would need some adjustments. He later gave orders to the team to use rough plays and after Gouenji Shuuya scored with Last Resort, he gave another order to Baek to do something about him. In the end, his team lost with a score of 3-2.