Aru was sacrificed because the residents of Tsuruguan Island believed that he was liked by the Thunderbird and could be used as a sacrifice to please the Thunderbird and pray for blessings. So Aru was selected as a sacrifice, and her tongue was cruelly cut off, her bones were pulled out, and her blood was drained until she died. He was then sacrificed as a living sacrifice to the Thunderbird to pray for the Thunderbird's blessings. The whole sacrificial process was an extremely sacrilegious and cruel treatment to Aru.