[ml1201]

It's about a girl who does kendo and is a maiden at her family's shrine when I demon called (I think) Zenki gets released, who kills these demons that are attacking. Then he tries to kill her but since she's the descendent of some priest she's able to bind him so he can't be in his full form, so now he goes around looking like a little kid. And then when she needs his help fighting demons she releases the seal.