Yakumaru is an esper who possesses the ability to manipulate liquids by altering their specific gravity. She shares the childish nature of her fellow Scavenger members but carries out her duties without remorse or guilt, even when it involves killing people and destroying things. Yakumaru hates teachers and views them as a source of evil in Academy City. She has been working with Leader for a long time and is perceptive enough to understand his plans after coming into contact with Misaka Mikoto, who defeated Seike earlier without being informed.
Yakumaru's abilities allow her to create various phenomena by mixing different liquids. In battle, she uses chemicals from her utility belt, including a special coolant that can quickly freeze an enemy and kill them when their heart and brain freeze over. This coolant is made by Yakumaru herself and improved upon the one used in Academy City. She also has baseball-like spheres that can be thrown at enemies like projectiles, causing a liquid thermite reaction with temperatures reaching 4000 degrees.