Ho Yinsen (Marvel Anime)

Ho Yinsen was Stark's friend during their recent capture from the Ten Rings and an enemy of Iron Man using the stolen Dio armor in the series.

Biography
His history was unknown. He was captured by the Ten Rings to assist Stark to operate in his injured heart by helping him build the minuturized arc reactor and secretly help him create the Mark I armor as their ticket to freedom. He was wounded in an attempt to delay the guards so the Mark I will be powered-up and ready to go.

Stark believed that he's dead then he took off.

But Yinsen was saved by a woman named Sandra and offered him to join the Zodiac. He was unknowingly corrupted by Karoda to destroy Iron Man by wearing the stolen Dio armor in exchange for power.

He revealed himself again in front of his old friend who was shocked by his appearance then Yinsen took off after he defeated him.

During the hostage crisis,he revealed to Stark that he created the Iron Men Sigmas by reverse engineered the Dio armor that suprised Stark.

Though he outnumbered him,he was defeated. After realizing the truth,he sacrificed himself to save Stark from Zodiac's wrath. On the ground,he apologised to Stark of everything he'd done. Stark forgives him.He died from his wounds. Tony have vowed to avenge his death on Karoda and Zodiac.