Guardian of the Witch

Guardian of the Witch (魔女の守人, Majo no Moribito) is a manga created by Asahi Sakano.

Plot
In a world full of Evils, humanity's only hope is the inhuman power of the witches. The city of Berne is on the frontline of the demons and there to protect it is the witch Manasfa and the kingdom's strongest knight Fafner. But what cruel fate awaits these two? A dark fantasy story featuring witches and knights begins now!