While Combustion is active your Fireball, Pyroblast, Fire Blast, Scorch, and Phoenix Flames deal 70% increased damage and reduce the cooldown of Combustion by 1.25 sec.
While Combustion is active, Flamestrike deals 35% increased damage and reduces the cooldown of Combustion by 0.25 sec for each critical strike, up to 1.25 sec.