Record of Havila War: Tales of the Butterfly

In the Amami Islands, a small humanoid species known as Havilans (or Butterfly People) has been discovered. To prevent their extinction, they are protected by humans, and breeding mates are assigned to them. Oshino, a young Havilan lad, harbors feelings for his designated mate Mai, but their relationship hasn’t progressed. One day, however, Oshino learns the truth about Mai’s real feelings and…
Source: Manga Million