Bo' Rai Cho is an Outworlder whose drunken and obese appearance hides a very skilled kombatant. He's appointed as the inventor of the Drunken Fist style in Mortal Kombat's universe. He's an important part of the lore as he is the one who has taught warriors such as Earthrealm champion Liu Kang, Shujinko and, later on, Kung Lao. His fighting style is somewhat infamous for using not only the Drunken Fist style, but also for using vomiting as a means to trap opponents, flaming farts and alcohol-infused spits to burn opponents, earthquakes and using his belly to ricochet on his opponents and bounce back. He is also a capable military general.
His name means "drunk" in Spanish and Portuguese.
A born Outworlder, Bo' rai Cho began to live in Earthrealm and to train Earthrealm warriors in the Wu Shi Academy. He never participated in a Mortal Kombat tournament due to him knowing that his status as an Outworlder would give the victory to Shao Kahn's faction. So instead he used his skills to train others.
When he heard of Liu Kang's death at the hands of Shang Tsung and Quan Chi, he began to teach Kung Lao his most revered technique - the Whirlwind Kick - so he could slay Shang Tsung. He then joined the Earthrealm warriors on the attack against the Deadly Alliance. He eventually would spy on Tsung's Palace and rescued Li Mei, a fellow Outworlder. The duo would then open way through the enemy Tarkata forces, who were led by Onaga, and, eventually meet the Earthrealm forces and retreat.
He would then fight among the Forces of Light in the Battle of Armageddon, but ultimately died.
He is first mentioned in Mortal Kombat's first reboot game, as Liu Kang's teacher.
Later, he appears in the comic sidestory of Mortal Kombat X. He comes upon Kuai Liang (Sub-Zero), who has just severely beaten by Hanzo Hasashi (Scorpion) and at the death's door. As he tends to Sub-Zero's wounds, he also says him to stop and reflect upon how he arrived there, and ask himself about what it all meant. As Sub-Zero recalls his life up to that point, he mentions his latest mission of obtaining a cursed Kamidogu dagger, which has possessed Sub-Zero.
As Kuai laments that he'll never be free from demigods and sorcerers, Bo' asks him if he still hasn't figured out what all these events up till now mean or why he is here. As Sub-Zero comtemplates commiting hara-kiri, Bo' laughs heartily and mentions that wine could help that melancholy. He also mentions that after all Sub-Zero has endured, Raiden owes him dearly.
Later, Bo' rai Cho hires the services of Kung Jin, a young archer, to steal a pen drive. He then tries to persuade Jin to join the Wu Shi Academy, but without success. He then gives Kuai the pen drive, whose content is a virus that is intended to end the cyborg Lin Kuei once and for all. He then goes with Kuai to the Lin Kuei base, and stays at the door to deal with any cyborg that tries to leave with "a stern lesson in Jojutsu". After the cyborgs were dealt with, the base explodes and before Bo' rai Cho could be roasted alive, Sub-Zero manages to freeze him for protection from the explosion.
Bo' Rai Cho is later seen again in the Story Mode of Mortal Kombat X, having a drink at the top of the Sky Temple, just as Raiden arrives there. After they talk about how much time has passed since they last have seen each other, they go to the Jinsei Chamber, where Raiden mentions that he had to disarm a trap set by Kano.
While Raiden is recharging at the Jinsei, he notices Bo' Rai Cho suddently being dragged out to the outside of Sky Temple by Shinnok. Shinnok then proceeds to torture Bo' Rai Cho. Although Shinnok mentions that he'd claim Bo' Rai Cho's soul, his fate is left unknown after that.