Have to admit... this miniarc came off rather weak. First of course we have the bringing of a child to slay giant monsters... Which though I might forgive for him being skilled enough, it would be hubris to assume you'd never slip up. The leader of the group has what seems like an incomprehensible reason for forging ahead, their baggage was resolved too quickly for any of us to give a damn and in the end it seems the entire thing was just meant to showcase his power.
Side note, I have to admit that it was a bit of a letdown that they basically just used his illness as a disposable MacGuffin to expel him from the adventurer's guild. As it stands that was a waste of a perfectly good plot.