Life steal

Life steal is an offensive stat that converts a percentage of the physical damage dealt by a champion's auto attack (and the small number of abilites that proc on-hit effects as noted below) to health regained.

Life steal is calculated from the actual damage done to an enemy, after armor reduction. Most champions begin with 0% base life steal. It can be increased with items and some champion abilities. There are no runes that increase life steal. The Vampirism mastery in the offensive mastery tree introduced in the Fizz patch increases life steal by 1%/2%/3%.

Champion abilities
Note: Only the life steal buff effect of these abilities is shown here, to read more information on each of these abilities, follow the link on each of them.
 * grants 5 / 10 / 15 / 20 / 25 % life steal for 5 seconds.
 * passively grants him % life steal.
 * increases his damage based on his health and gives him 9 / 12 / 15 / 18/ 21 % life steal for 6 seconds.
 * grants him 50 / 75 /100 % life steal for 20 seconds.
 * suppresses an enemy champion for 1.7 seconds while dealing 5 strikes for 33% of his attack damage plus some extra damage and granting him 30% additional life steal for the duration. The damage done from the ability will proc all life steal he has.