Ryōka Yamakawa

Ryōka Yamakawa is a Gewehr user. Her Gewehr is an Ingram MAC-10 machine pistol.

Ryōka is in Seitetsu Class 5 of the second grade. She has, before her transformation, the appearance of a young idol for her age, but her appearance is that of a grown woman after she transforms to her Kämpfer form. Ryōka appears for the first time in the municipal library on the second floor.

Ryōka seems to be afraid of everything, especially the Blue and Red Kämpfer. She says "I'm sorry" when she makes a mistake.

Ryōka's voice actress, Kotomi Yamakawa, shares her surname with the character.

Ryōka's personality is samiliar to Ururu Tsumugiya from Bleach.