Kenji Todoroki

Kenji Todoroki, also known as Ken (ケン), is a student in Class 1-A at U.A. High School, where he got in through official recommendations and is training to become a Pro Hero. He is the youngest son of Endeavor, the retired Pro Hero, and is one of the main protagonists of the series.

Quirk
Half-Hot Half-Rock: Kenji's Quirk gives him the ability to generate earth from the right side of his body, and generate fire from his left side.

Due to years of rejecting his father, Kenji has developed a habit of favoring earth, even when the fire would be a better option. This grudge also caused him to have difficulty controlling his fire. While he is capable of using both elements simultaneously, he isn't used to doing this and still needs to practice dual-wielding. While training for his ultimate move, he claimed that using both abilities at the same time slows him down.

If he overuses one element without utilizing the other, then his own body temperature will suffer. The earth half will cause stiffness and the fire half will cause heatstroke. Until his bodily limit is reached however, neither has any visible effect on his body. Kenji can easily negate this weakness by alternating between earth and fire.

As part of his training, Kenji stood in a row of hot coals and alternated between using earth and fire to regulate the temperature of the coals. It helped his body become accustomed to the rocks, and he learned better control over his flames.