Does anyone know about a philosophical manga that deals with the nature of humans,death x ...

anything from shoowa or Kano could be great :)

check out xxxholic (clamp)

most manga in seinen genre are like that. check out Tokyo Ghoul and Ajin. they are my favorite

Hunter x hunter (chimera ant arc)

http://www.mangago.zone/read-manga/20th_century_boys/ And anything by Urasawa Naoki
http://www.mangago.zone/read-manga/holyland/
http://www.mangago.zone/read-manga/a_falsified_romance/ For me, the manga gets so into the philosophical aspect that the characters get swallowed up and made stale by it, but it's good if you want something really philisophical. It's based on Crime and Punishment.
http://www.mangago.zone/read-manga/heads/
http://www.mangago.zone/read-manga/parasite/

http://www.mangago.zone/read-manga/death_note/

i second this

Thank you very much guys (●'◡'●)ﾉ