Combustion is a mage ability that when activated, gives increasing critical strike chance with Fire spells until 3 criticals occur. Each time a fire spell is cast, the chance to get a critical strike with fire is increased by 10%. This effectively guarantees at least 3 critical strikes from Fire spells within the next 13 casts. This ability is talent trained, requiring 31 points in the fire tree, making it popular with fire mages. It is very valuable when intelligently coupled with the Fire talent Hot Streak.