Laconic / Zettai Hero Project
aka: Zettai Hero Kaizou Keikaku

Weakest hero alive has to endure procedurally generated Training from Hell to stand up to planet-destroying Final Boss.

Alternative Title(s): Zettai Hero Kaizou Keikaku

http://tvtropes.org/pmwiki/pmwiki.php/Laconic/ZettaiHeroProject?from=Laconic.ZettaiHeroKaizouKeikaku