Kemono Jihen Vol. 5 by Sho Aimoto
In a snowy village deep in the mountains, twin boys were born. The older, Yui, was strong and gentle, and the younger, Akira, sensitive and a bit of a crybaby. The two were separated when Akira left the village, and now Akira is thrilled to have found his brother again. But Yui has changed, and has strange new powers. What has become of him?