Keys is a Manga/Manhwa/Manhua in (English/Raw) language, Action series, english chapters have been translated and you can read them here. You are reading chapters on https://mangabtt.com fastest updating comic site. The Summary is
One tragic night, Caine survives a brutal assault when a demonic entity known as a Key saves his life. With his chance at a normal life long gone, Caine must accept his fate as a Key Holder possessed with remarkable supernatural power. But this power comes with a price. The Key inhabiting Caine has its own goal: the eradication of every other Key. Caine must harness the strength of his Key to find his place in the hidden world of hostile Exorcists, sinister Keys, and a network that spreads far beyond his hometown of Derry, Northern Ireland.