leaderChange Cats start leaving…

Cats start leaving the other camps to live with the rogue River Ripple on his island. River Ripple later becomes Riverstar, the first leader of RiverClan.

Acting leader during series 5. Book 5 is when the forest is divided into territories, and cats can choose to follow River Ripple. Riverclan is formally given its name in Book 6, so technically he doesn’t officially become the “leader” until then)