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.
When playing this build depending on who I am facing is what I may get. I generally go for 2 Zonyia's Rings, if not 3 when going against a soft team.
Start withand 2. Then as quickly as possible get soul stealerand finish your boots.
At this point you should have at least 5 stacks, now is the time to build the OP item for Kat. Here comes the biggest choice for Kat if kills are easy to come by and you have a reliable tank in group build 3. But if you are having issues with staying alive build any combo for the next 3 items betweenand.
Not only will your ult be a pain in the ***, but your shunpo will hit for 1k a jump.