Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Berserker Rage : (passiv): For each 1% of health missing, Olaf's attack speed is increased by 1%.
Undertow : Damage: 65/110/165/200/245 + 30% of Attack Damage
Slow: 24 / 28 / 32 / 36 / 40 %
Vicious Strikes : Damage: 12/18/24/30/36 (+ 0.4/0.7/1/1.3/1.6% of Max Hp)
Lifesteal: 9/12/15/18/21% Spellvamp: 9/12/15/18/21% Last 6 seconds
Reckless Swing : Damage dealt: 100/160/220/280/340
Damage taken: 40/64/88/112/136
Ragnarok(Ulti) : Immune to disables, Flat damage absorption:25/45/65
Passiv : armor penetration 10/20/30
Ghost is really useful for Olaf, u can easy catch some 1 or run away with ulty on.
Exhaust same as ghost slow some 1 to finish him or slow to run away.