can anybody recommend me some manga with a character who has lived for a really long time ...

Immortal rain maybe? It's Shoji though. It's about Methuselah.

Shojo* sorry. Typing on phones suck

thanks but i've read that one

How about this one? :D
http://www.mangago.me/read-manga/immortal_rain_shinigami_of_the_east/ and the sequel
http://www.mangago.me/read-manga/immortal_rain/

Ah sorry forget it...i didnt saw the other comment. >.< (Still a lil bit tired xD)
This one is really nice!~ :D
http://www.mangago.me/read-manga/eat_man/

thank you