they are the princes of fukui, twins, and have black hair. riku is the elder twin, charming, playful, energetic, a jokester and a tease. ren is the younger twin, stoic, apathetic, aloof, serious, forward, and quite private. riku tends to do the talking for the both of them, while ren tends to just listen. if ren does speak, it is short and simple, sometimes coming off as rude and blunt. riku can come off as chatty and informal. they are both hopeless romantics. they always stick together.