A jungler has the trickest role to define, as far as what champions do best here. It is a varied role, because many champions are able to do this. But for the most part, the typical jungler is one who can survive fighting the jungle camps, usually with enough health left over to gank one of the lanes. Because of this, typical junglers usually have a higher health pool, some sort of build in sustain like life steal or spell vamp, and specifically use the Smite summoner spell. Another characteristic of a good jungler is that the champion has a high gank potential, meaning that when they pop out of a bush, they have some damaging crowd control effects that allows them to pick off targets.