So i'm looking for this old manga so i can finally finish the story.

The setting is medieval japan, with supernatural stuff like Demons and Youkais. I believe it was Seinen, but i'm not sure.
There's this super strong giant demon, and he's going to be exorciced, but the exorcism is not done completely and he becames a child, with no power.
He's wounded when he's found by a human girl that helps him.

-There was no translation, so i was reading in Japanese.
-There was at least 2 full volume released.
-The First volume cover it was just the Demon in his child form. (i think it was bluish)
-The Second volume cover he was caring the human girl in his back.
-The artwork is singular, not too mainstream (maybe it was kinda underground)
-I found that manga in 2012/2014 (can't remamber)
-The name is very much JAPANESE with no english/foreign words (the reason i can't remember!!)

I can remember all this, but not the freaking name T____T

Please, if have any idea, please help me.
Thank you very much.