He has black hair and has orange sunglasses. T hid his blindness (Bong-Sa literally means 'the blind' in Korean. His nickname is a pun made by other Judges based on a Korean short story known as Shim Cheong Jeon, where the character of the same name appears with blindness), surprising Mo-Ri. He has a long and pointed nose and shark-like teeth.
After he was killed and resurrected, he gained an X-shaped scar similar to those of Baek Seung-Chul.
T is a caring, fatherly man. He meets Yu Mi-Ra at a supermarket and has a quick talk with her, explaining how she should 'balance' her power and flexibility, reaching the peak and true meaning of the Moonlight Sword technique.
He reveals that the one who blinded him was a user of the Moonlight Sword. Yet, he does not blame nor hate Mi-Ra for it.
He was a South Korean spy who infiltrated North Korean mines, posing as Jeong Su-Shim, a North Korean arrested for watching South Korean drama. He ended up working in the mines alongside Lee Soo-Jin. He had tried to save Soo-Jin, who was knocked out at the time, by using his Charyeok beast. He asked his Sapsal Dog to take her away from Ryu who insisted on killing everyone to leave no witness. He told the half-conscious Soo-Jin to live free. Ryu then tried to kill him to find Soo-Jin, but instead of killing him, he used his Moonlight Sword technique to blind him. 
A Round with God/Eclipse
He is the announcer of metropolitan league right before the battle against Mi-Ra and Byun Jae-Hee (which is technically the final match arranged by Mu-Bong to keep the participants together during the nationals and thus keep them at a safer situation), and he is killed by Drake McDonald. Judges are enraged, including O, who was portrayed with a playful, friendly personality.
World Tournament Arc
Bongsa is revived at an unknown point by Ultio R. He has seemingly lost most of his memories, but this is not confirmed. He is the announcer of the G.O.H World Tournament. During the match between Team South-Korea and Team France, he sensed Judge P using her Charyeok, and went to look for her. He later found and subdued her. He later arrives, with the captured Judge P, along with the Morning Crows and Ultio R to the battlefield, after the battle with the King. Ultio R stole the Power of the King and opened a portal to the Heavenly Realm, with the help of the Morning Crows and Shim Bongsa. Shim then once again engaged Judge P, who had gotten up. Despite Judge P now focusing only on the battle, she lost to Shim. Despite his victory Shim was surrounded by the Judges, who had defeated the Morning Crows. Shim managed to escape, with the help of Bishop Sang Man-Duk and his current location is unknown.
RE: A Round With God
It is mentioned by Q multiple times that Bong-Sa is a very skilled swordsman, and is shown in his conversation between Mi-Ra. Judge P was also shocked when realizing there was apparently somebody who could defeat T with a sword. According to Q, T cannot practice or use Charyeok in battle, but his skill level is very high and even someone with ability to use Charyeok cannot defeat him. He was also able to sense the presence of Drake McDonald in the tree when the latter was hiding to attack Yu Mi-Ra. After being revived, he was strong enough to be able to beat Judge P.
Sapsal Dog (삽살개)
A black, shaggy furred dog with a thunderbolt symbol on its head, it is unknown what abilities it possess. It was last seen being able to fly.
He used this sword against his fight with Priest Ryu in the past.