Request Forgotten manga

Okay I know I placed a same one but not much answers maybe due to the absence of many nudders or something anyways this manga forgot the name but I remember the parts of it its basically its set in london about a police officer on a case and where his twin dies in the end and the other one gains some abilities from the murder that the twins was on a case then later on a I think japanese women arrived and she liked the twin that died. It is also like japanese youkai and ghost but in western Europe type that's all

 

http://mangapark.me/manga/arago

 

sorry if wrong only one I could remember that fits the description

 

Yeah it's arago

 

I remember a korean or chinese series similar to that. You sure it's Japanese and set in London?

 

definitely arago if it's included some celtic myths and the four horseman

 

Thank god finally I mean I read this around 2012 or 13 and then I thought of oh why not a recount and then forgot the name