Manga debut - Chapter 12 "The Obvious Thing"
Nami Kusunoki has the power to freeze water to form any shape she chooses, usually forming it into claws to augment her martial arts, and launching them like bullets to pierce and freeze her targets.
She originally hated Comrades, especially those with fire-based abilities, but after spending time with Taisuke , her grudge begins to dissipate.
Her little brother Satoru was burned alive before her eyes by Kanon's ability and that was the reason Nami hated Comrades in the first place.
It's possible that she has some feelings for Taisuke as she names him as her reason for living in the second arc.