How come Karkat is supposed to lead the new race of trolls? I thought the troll's game going to shit and the creation of Bec Noir was all Karkat's fault, wasn't the point that he was always a crap leader?

Karkat was a decent leader he managed to unify the trolls after all. The troll session was actually fairly normal, it didn’t go to shit at all. The creation of Bec Noir can be pinned on Gamzee and Vriska (go figure).