Mimizuku and the King of Night

Mimizuku to Yoru no Ou
ミミズクと夜の王

Source

Horned Owl and King of the Night
Mimizuku to Yoru no Ou· ミミズクと夜の王
novel

Mimizuku, a small girl with chains on her wrists and ankles and the numbers "332" branded onto her forehead, wanders into the Forest of Night seeking to be eaten by a monster. However, when the ruler of the monsters, the mysterious and beautiful "King of Night," refuses to eat her, she tries to formulate a way to convince him otherwise.