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.
This is my build that i have created over time, absolute rape. the huge movement speed along with ghost makes for easier ganks or running. the extra lifesteal makes you nearly unstoppable at low health along with the dodge and high attackspeed. Phantom dancers are amazing such great stats for olaf... many times i have taken a whole team on solo, the majority of the fight i have been on around 10-20% hp. Epic win of a build.
I dont really feel like writing a big thing on how to play olaf, if you want that look at some other build. However i would like to mention that undertow should not be used for harassing or doing any significant dmg in a fight, it should purely be used for the slow to either chase someone down or to run away from someone. I see too many people leveling it up first and throwing it at the enemies constantly. It uses far to much mana and does hardly anything and when **** really hits the fan you can do nothing but auto attack.
Anyway this is my 10 minute first attempt at making a build. Epic win. Good hunting,