Genki Sakura

A 10-year old elementary school boy that is sort of the 'leader' of the group. He has a good heart, and he truly cares for his friends and the monsters. His goal is to turn all of the evil monsters into good monsters again. Determined, optimistic, and hopeful, Genki is a real go-getter. Genki also directly fights enemy monsters by donning his roller blades in combat.

He is also surprisingly strong for a 10-year old (he has shown to be able to lift objects several times his own weight from time to time in the series), although whether this is due to his own innate strength or because he is in the game world (thereby having been subjected to some game mechanic) is not known.

(Source: Wikipedia)