Numer is a slube with a nervous disposition exacerbated by his own self-doubts. These self-doubts make him look small, even though he’s the average height for a slube at 1.8 meters. I guess he has a strong heart, though, since he goes on the insane escapade of Slubes in order to help his new friends. In fact, his heart probably overpowered his mind to get him to do it.
A few years before Slubes he moved from Gelago City to the town of Nottle for a quiet life. He doesn’t have very much of a can-do attitude: he tends to sleep in past noon, which is what puts him on the path to being the happenstance hero. Although he’s unsure about the journey to rebuild the ancient crystal, he agrees to do so to be close to his secret love, Cherry. See? His heart DID overpower his mind!
He’s given a mallet that can shoot energy beams by Zeth to ease his nerves, but unfortunately it turns out that Numer really will have to use it. Can he do it even without a can-do attitude? Or can he find a do… attitude? Well… I think he can. That’s gotta count for something, right?