Momoyama Kyoudai
桃山キョーダイ
Arima and Chihiro are twins from the Momoyama family. When they were young, they overheard their parents mention that they would be told a truth on their 16th birthday. For six years, the siblings feared they might be adopted. However, the revelation they receive on their 16th birthday turns out to be far more surprising than they imagined.