Chuuya— Preference.

Chuuya has a younger brother... named Fumiya. He also has his childhood companion, Dazai, whom he found when they were 5 years old. Dazai was peculiar; he was human... but he had fox ears and a tail.
Two years later, the government announced a new creation, "hybrids"—the same type as Dazai... except they appeared much later and there was a variety of them.
Now Chuuya is 17, Dazai is also 17, and Chuuya's brother is 7.
Dazai lives with Chuuya. His mother is Kouyou; he has no father. Fumiya was very spoiled and loved by Chuuya, which made Dazai feel bad.
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Right now, Dazai was being pampered by Chuuya... but Fumiya arrived and literally replaced Dazai, now being the one getting pampered.