The Mandarin appears as a boss in Marvel: Ultimate Alliance.
The man that would become the Mandarin was born from an English prostitute in an opium den located within the small village of Habuquan in Inner Mongolia, China, where he spent his entire childhood doing forced labor. Following his mother's death due to overdose, the Mandarin killed her procurer, whom he figured was his father, and delved into a life of crime. The rise of the communist revolution saw the Mandarin becoming a fugitive. While running away, the Mandarin found inside a cave in the Valley of Spirits the wreckage of an alien spaceship, and its passenger, the moribund Axonn-Karr. Becoming transfixed by a set of ten small cylinders spinning in the ship's engine, the Mandarin finished off Axonn-Karr and took the artifacts despite the alien's pleas. Having found them similar in appearance to rings, the Mandarin started wearing them as such, slowly studying each of them and gaining access to their powers. When the Mandarin has first worn them all at once, his mind was reached by the warrior spirits trapped within the rings. These spirits influenced the Mandarin so his ultimate goal in life would be to resurrect them.
With the power of the rings, the Mandarin subjugated the villages around the valley. Taking the alias of the Mandarin, he became an influential weapons-runner and a power that not even the Chinese Army could successfully challenge. As he grew in power, the Mandarin attempted to escape from his past. When offering accounts of his early life, he would present himself as a respectable and educated aristocrat, born from an English noblewoman and a direct descendant of Genghis Khan. It is very likely the Mandarin even became delusional, and, consumed by his own lies, started believing in them as if they were true. In an attempt to unlock the true potential of the technological wonders he wore as rings, the Mandarin allied himself with warlord Wong-Chu. Targeting the supply lines of American weapon-manufacturing company Stark Industries to the American military forces stationed in Afghanistan, the Mandarin lured the company's CEO, genius inventor Tony Stark to the country. The Mandarin intended to force Stark and his fellow prisoner, Ho Yinsen, to unlock the secrets of his rings.
In the meantime, Wong-Chu ordered Yinsen and Stark to build weapons for him. The technology they were given access to was instead put to use in the creation of an armored suit with which Stark escaped captivity after Yinsen sacrificed himself to buy him time to charge up the suit. The development of these events gave the impression the armored Stark was actually a bodyguard who had previously rescued Stark before taking on Wong-Chu and his camp. From a distance and remaining unnoticed, the Mandarin witnessed Stark's escape as Iron Man, but decided not to intervene, for he had finally found his true nemesis. The Mandarin's first true encounter with Iron Man occurred when the armored hero was sent to China at the request of the US military high command and the CIA. Iron Man smuggled himself into China and was airdropped near the Mandarin's castle. He fought his way through the Mandarin's troops and the pair confronted each other, however, the Mandarin's power rings were able to incapacitate Iron Man and he was taken prisoner.
The Mandarin then attempted to have his minions examine Iron Man's armor, but it was too well protected for them to learn its secrets. Iron Man eventually revived and broke free from his imprisonment and engaged in a rematch against the Mandarin. Iron Man's armor was heavily damaged and Stark himself seriously injured battling his foe, but managed to escape after detonating the Mandarin's castle. Following his battle with Iron Man, the Mandarin then began to study his foe. Learning that Iron Man was in the "employ" of Tony Stark, he believed that this was an attack on him by the western world and began accelerating his plans for global conquest, ordering his sleeper agents all over the globe to become active.
Marvel: Ultimate Alliance: Story
The Mandarin joined Doctor Doom's Masters of Evil, but was rejected after attempting to take control of the team from Doom. To get revenge from him, and to mislead the Ultimate Alliance in their search for Doom, Loki shapeshifted into the Mandarin in Atlantis in order to get the Alliance's attention on him, and to chase him to his castle. After his guards, composed by Dragon Man, Ultimo, and Grey Gargoyle, were beaten, the Mandarin was confronted by the Alliance and defeated, where he revealed they were tricked by Loki.