Rengar

Rengar, the Pridestalker is an upcoming champion in League of Legends.

Abilities
Rengar's abilities don't have a cost related to them and their use is only limited by cooldowns. Instead he uses Ferocity as his secondary bar.

Rengar builds 1 point of ferocity with each ability he uses on enemies (including structures and neutral monsters). Having 5 ferocity empowers Rengar's next ability, but drains all ferocity. Upon reaching 5 ferocity, each of his basic abilities become available to cast. This does not refresh Rengar's cooldowns and they will continue to count down in the background. Upon consuming the ferocity, the empowered ability is put on full cooldown and any unavailable abilities become unavailable once more.