Tai Lung

"He's a panda! You're a panda! What are you going to do, big guy? Sit on me? *chuckles*"

- Tai Lung confronting Po for the first time

Tai Lung is the sole antagonist of Kung Fu Panda. He was Po's enemy, Shifu's former student and adoptive son, and Tigress's adoptive older brother.

Beginnings
Tai Lung was found as an abandoned cub by Master Shifu. Shifu raised him as his own son, showered him with love, and trained him in the arts of Kung Fu.

Tai Lung became a formidable fighter, and was the first to master the thousand scrolls of Kung Fu, but even that power wasn't enough for him. He lusted for the Dragon Scroll, which was an artifact believed to hold the secret to limitless power, as he grew steadily more prideful.

The day arrived when Shifu felt that Tai Lung was ready for the Dragon Scroll, but Shifu's mentor, Grand Master Oogway, respectfully refused to let him have it due to Tai Lung craving the scroll for selfish purposes. At that point, Tai Lung's pride dissolved into rage, and he rampaged through the Valley of Peace, laying it to waste. He then attempted to take the scroll by force, barrelling through the thick wooden doors into the Jade Palace's Hall of Warriors, where Master Oogway and Master Shifu were waiting for him.

Shifu attempted to stop Tai Lung from getting to the scroll, but was unwilling to harm the one he considered to be his son. However, Tai Lung had nothing but hatred for Shifu, due to the fact that Shifu was unable to stand up for him when Oogway denied him the Dragon Scroll, and violently pushed Shifu out of the way, incapacitating him in the process. Just before Tai Lung was about to get hold of the Dragon Scroll, he was stopped by Master Oogway, who blocked his chi, rendering him unconscious.

He was then locked into a prison with thousands of guards, weapons, two boulders chained to his arms, and a jade shell on his back to immobilize him as punishment for his crimes against the Valley.

In Kung Fu Panda
20 years later, Tai Lung escapes from Chorh-Gom Prison; meanwhile, in the Valley of Peace, the potential Dragon Warrior (Po) is being trained to fight Tai Lung. But the problem is that while Tai Lung was locked away, he had much time to meditate, and became stronger than ever before. He is faster, stronger, and now more powerful than his former father and teacher Master Shifu.

During the final battle, he and Po came face-to-face and fought over the Dragon Scroll, trying to outdo each other to retrieve the scroll (that was before Tai Lung could kill Shifu with his claws for the scroll when he found out it was gone because Po took it).

After the fight, Po managed to defeat Tai Lung by using the Wuxi Finger Hold, which caused him to burst in a rippling golden wave.

Trivia

 * Tai Lung appeared in the first Kung Fu Panda video game, in which he was the primary villain again and, just like the movie, broke out of jail and went for the scroll; however, unlike the movie, the Furious Five get captured by the leopard and his army of wolves. So it is up to Po to go rescue them and stop Tai Lung.
 * He returns in the video game Kung Fu Panda: Legendary Warriors, in which he's the main villain (again) and also the final boss. This time, he comes with a troop of enemies to aid him. He's once again stopped, defeated, and killed by Po and the others.
 * According to the creator's commentary, the colour gold was used to symbolise heroism in the movie, and that Tai Lung saw himself as the hero of the story, hence they gave him golden eyes.