>>10930629The problem with your request is the idea of manga itself: No one writes a story where a protagonist kills himself on the first page.
However if you want to read just a gory manga then there are a decent selection to choose from.
Inio Asano for example is a known author of such, in both physically and mentally gory art.
Also:
Blade of the Immortal
Ichi the Killer
Shigurui
Franken Fran (also the sequel)
Gantz
Freesia
Higurashi no naku koro ni manga
I am probably a bit outdated regarding stuff coming up during last five years.