Riko Suminoe is the younger of Keita's twin step sisters.
There are two ways to distinguish Riko Suminoe from Ako suminoe one of them is that Riko wears her hair up in a ponytail that however is not 100% accurate due to the fact when she is asleep or whatever she wears her hair down. Furthermore the best way to tell the the bandage she wears on the left side of her face. Riko is the less perverted sister however she is honest and more blunt with her answers making people flip out often. While she may be honest she is love shy in public and believes love should be done in secret not in public. Riko unlike her sister ako has bad achohal tolerance and passes out fairly easy Ako has use this to try to get ahead. Riko is better than Ako at p.e and biology however she got into the school by rolling a lucky pencil. ven that being so in middle school and high school she is and has been head of the disciplinary committee.