The Witch and the Hundred Knight 2

From Gematsu:
"An incurable illness that only affects girls.

—“Witch’s Disease.”

An eye harboring mighty power appears on the foreheads of those infected as proof of the disease. When the eye opens, the girl loses her sense of self and becomes a “witch” who destroys whatever she desires.

“Kevala” is a world corrupted by the Witch’s Disease. The people live in fear of witches. A girl named Amalie living in a remote village even lost her parents to a witch. She lives a modest life with her younger sister Milum, the only immediate family she has left.

One day, Milum suddenly disappears. Amalie eagerly searches for Milum, but she was nowhere to be found. Just when she was about to give up on the search for her sister, Milum shows up back at the village covered in mud.

In her hands were “Flowers of Mana,” a present for the older sister she loves. And on her forehead was the witch’s eye that was the enemy of their parents…"