Kimi ja Nakya Dame Nanda.  

Kimi ja na Kya Dame nan da, 君じゃなきゃダメなんだ。

Nanoka, who believed herself to be an orphan, was taken aback when her grandfather disclosed that she had a sibling prior to his demise. Upon visiting the specified location, she encountered two individuals at the entrance - Aoi with blonde hair and Kou with dark hair. Can you determine which of these two is your genuine brother?