Hello, thanks for taking time to help me.

I have been trying to find the name of this movie since I was back in school

It's a Japanese, Chinese or Korean film about a guy that hunts ghosts

He is cursed and every partner he has always ends up dying, The guy is real shy and he falls in love with a girl that works in a hospital, she lives near him

Anyway one of the ghosts he has to fight is a water god and possesses his new partners body

Also I remember the gun they have, there's a little pin on the trigger that draws blood and coats the bullets to kill the ghosts.

I have been trying to find this movie for so long.

Also I would like to know any similar films.