Todoroki

Todoroki is a minor character in the A Certain Scientific Railgun series. He is a student of Habatobi High School and is an esper of unknown level whose power involves the manipulation of water particles.

Daihasei Festival Arc (Railgun)
He is first seen with his partner Amime competing in the three-legged race against Misaka Mikoto and Kongou Mitsuko from Tokiwadai Middle School, two female students from Airin Girls' High School, and two female students from Ninoudefukozu Middle School. When the race begins, he and his partner are bound in asphalt-hardened bandages by the girls from Airin, and only after those girls gain a significant lead do Todoroki and Amime manage to free themselves.

When Amime uses his power on the soles of his and Todoroki's shoes, Todoroki uses his own power to create a fireball. He plans to use his power alongside Amime's to propel them to the finish line, but he unknowingly lights a loose bandage on Amime, causing them to fly out of bounds. He and Amime are about to crash into a little girl when the two of them hit a flying shock-absorbing mat launched by Mikoto and Mitsuko, land on the ground safely, and are doused by security bots. Todoroki then discovers iron sand on himself, and Mikoto reveals that she would've stopped him and Amime from moving if they seemed like they would win. She admits that doing that would've been unfair, but since the iron sand saved their lives, she asks them to forgive her. He then asks offhand whether that was the way ojou-samas do things, and gripes that those tactics have no openings.

Ability

 * Manipulation of water particles: His ability isn't named, but it involves the palm of his right hand gathering, breaking down, and heating up the water particles in the air.