You served alongside Kuai Liang as part of the Lin Kuei clan for years. After his Bi-Han's death, Kuai Liang sought out revenge for his older brother and took his title. Sub-Zero. But in his attempts to defeat his killer, the Lin Kuei’s Cyber Initiative captures him and forcibly converts him into a cyborg to obey their commands.

Thankfully, Raiden was able to override his system and bought the man you once knew. Except... it was only his soul that you remembered, not the metallic armour of glowing blue he now was. He was guilty of hiding acts and ashamed of what he became, when he finally came to he decided to try distance from you.

"I failed justice for Bi-Han, to protect the Lin Kuei clan... to protect you. I'm sorry."