Mad Devil Yankee

Mad Devil Yankee (マルイドヤンキー, Maruido Yankī; Viz: Maruido Yankee) is the B-Class Rank 4 professional hero of the Hero Association.

Appearance
Mad Devil Yankee wears a light-colored cargo button-up shirt, a belt, and cargo pants. His shirt sleeves and pants are rolled up slightly. Across his chest is a strap with a patch on it. "Mad Devil Yankee" is written on his left sleeve and "Devil" is written on his chest patch. He sports an undercut for a hairstyle and wears a bandana on his forehead.

While pretending to be the fake hero "Papillon 800", he wears an outfit comprised of dark-colored armor with a large figure of a butterfly on his chest and a relatively small pair of butterfly wings on his back. On his face, he wears a butterfly shaped mask.

Personality
Mad Devil Yankee has strong resolve and heroic tendencies, he takes great inspiration from Mumen Rider, and is remorseful about his involvement in the rigged hero gambling scenario.

History
As a former delinquent, Mad Devil Yankee became a hero after witnessing Mumen Rider's valiant efforts against Deep Sea King. When told to play a part in the rigged hero gambling scheme, he refused saying it was an insult to heroes. McCoy reveals that his mother was receiving special care within the Hero Association Hospital and essentially threatened to remove her treatment privileges if Mad Devil Yankee didn't comply.

Neo Heroes Introduction Arc
Dressed as the imaginary C-Class Rank 333 hero "Papillon 800", Mad Devil Yankee arrives to the area of the staged scenario where he encounters Shiverhuahua. He reads lines off his cue card and attacks the monster assuming he will win decisively. Shiverhuahua turns out to be far stronger than expected and proceeds to beat up Mad Devil Yankee.

He becomes badly wounded and thinks he might lose. After telling McCoy to give word to his mother that he left the city and found a real job, he makes one last attempt to assault the monster. Saitama then arrives and kills the dog-like monster, saving him. Mad Devil Yankee soon passes out from his injuries and when he awakens he realizes he is being ridden to the hospital by Mumen Rider.

Abilities and Powers
As a high ranked B-Class hero, Mad Devil Yankee is presumably quite powerful. He was easily overpowered by Shiverhuahua, a supposedly Wolf-level Mysterious Being, although he wondered if its actual disaster level was only Wolf.

Physical Abilities
Enhanced Durability and Endurance: Mad Devil Yankee was able to endure multiple hits from Shiverhuahua, a dog-like monster that could send him flying with a single blow. Despite the heavy bruises and bleeding, he managed to keep on fighting before finally becoming unconscious, similarly to how Mumen Rider stood up against Deep Sea King.