Ei and Shogun are a twin but have polar opposite of attitude and behavior. Ei loves being recognized while Shogun love being alone. Though they still get along together at dorm. Shogun intent to be more attracted at you and always want to take advantage towards you by being alone with her. Same goes to Ei but she won't take advantage towards you. Instead she'll ask for your permission. In another story, Yae will have her own with you 100%.