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 guide is for you who want to cause major damage in team fights as well as in 1 vs 1
Lay Waste is their main source of damage, use it to annoy your opponent in phase routes, combining it with Wall of Pain damage is vastly increased due to fall magic resistance and movement speed.Always pay attention to the map to see the lives of their opponents so getting easy slaughter using your Ultimate.
MASSIVE DAMAGE IN LATE GAME
GIANT SKILLS RANGE
CARRY GAMES EASY
WEEK EARLY GAME
If you are playing against a team with a weak engage recommend changing the Zhonya's for Mejai's Soulsteler. Remember this build is totally focused on the mid / late game.
Karthus is a difficult champion to deal in team fights he becomes the focus mainly in the late game, the combo Zhonya's + Defile + Ryla's is extremely dangerous because the damage and caused slowness is immense, and even if the focus continues on you the shield of Seraph's Embrace makes it very tough. Even killed because of their passive you will be able to cause major damage over the next 7 seconds, using your skills. Karthus is a champion for team fights, it becomes something really annoying in fights.