Overview
If you’ve ever thought that an enemy would die if someone would so much as breathe on them, or you’ve clicked on their portrait and saw that they survived with literally 1 HP, then I’ve got good news for you. There is something you can do about it. Introducing: Karthus. Just press R and you will kill all those lucky dogs that escape from your all-in or your teammate’s all-ins. He’s a jungler that can literally gank someone from his own fountain! Click here for the latest data on his best builds, including Runes, Items, Summoner Spells, and more.
Keys to Remember About Karthus
Just press R when enemies are low HP.... Yeah. That's the trick to playing Karthus. Actually, it does require you to pay attention to the map. One other thing is Karthus can also ult to start a fight -- for example, if you see your team about to commit to an all-in on the other side of the map (or if they're about to get dove), it can swing the fight for them. Saving it until after the fight might net a kill, but it might also get your teammates killed (whereas using it at the start of their fight might keep them alive).
Late game, your job is to jump into the clump of enemies and then die. You become a zone of damage they can't easily traverse and then you can pop your ultimate quicker to help your team. Saving your ult strictly for low health enemies who are running away is extremely greedy and often the wrong play late game.
Strengths
He has great clear speed thanks to having a ton of damage in his kit from the get-go, which means if he’s able to farm unchecked, he’ll quickly scale and become an early menace. The faster he is able to reach level 6, the better for your team, as he’ll immediately be able to pressure the entire map with the global range on his Requieum [R]. This allows him to either secure kills or help allies with a little bit of extra damage during all-ins. This pressure remains throughout the entire game, as enemies will be aware that any time they escape with a sliver of health, they’ll be in striking range of Karthus. In fights, he wants to get into the thick of the action and deal as much damage as possible before his Death Defied [P] pops -- he’ll have 7 seconds to unleash hell, which is great if the enemy team is unable to move much.
Weaknesses
He’s weak in duels early because it’s fairly easy for enemies to evade his Lay Waste [Q], which accounts for the vast majority of his damage in a skirmish situation. He also lacks in hard CC, and these two factors combined means his early ganking potential isn’t very good -- you’ll want lanes that can fend for themselves, or even better, lanes that can help you if you are invaded by the enemy jungler. And before he gets items online, his ultimate doesn’t deal a ton of damage -- it’s a tool to finish people off or add chip damage, but it doesn’t have the immediate oomph that most other champions bring to the table at the start of the fight.
Game Plan
Early Game: Just power farm and look to rush level 6 as quickly as possible. You can counter-gank for lanes that have CC, but in general focus on leveling.
Mid Game: You can look for fights at most points in the game as long as your ultimate is up -- it’s a lot of guaranteed damage across the enemy team and as long as your team can fight properly, you shouldn’t lose any fights too terribly.
Late Game: Same idea as mid-game, though you’ll have a lot more power at this point in the game. You want to make sure that you die during a team fight -- if you are picked out early, the enemy team can peel back after your ultimate and sustain themselves back up.
