Thanks to Karthus's K/D/A and utility, he has a somewhat poor overall win rate. He does best in the late game, with a winrate of 54.4% in that phase. Unfortunately, he does worst in the early game, where Karthus's winrate is 45.1%., The difference between his best and worst game phases is a large 9.3%. This large difference makes it clear that his power spikes and fades in different phases of the game. Plan accordingly.
Karthus has been picked only occasionally in the latest ranked League of Legends games. In the current meta, his popularity is 2.7%. He is rarely banned during champion select. Obviously, very few players see him as a huge threat. In the latest ranked matches, Karthus was banned 1.6% of the time.
You will find him typically used in the jungle position. However, that is not the best position for him. The top win rate position for Karthus is bottom (48,3%). Currently, Karthus's meta game is centered around dealing damage. In particular, his kit should mostly be centered around magical damage. Dealing physical damage is the least critical part of Karthus’s build.
If you are not familiar with his skills and gameplay, you may find it difficult trying him out for the first time. Many competitors believe him to be a difficult champion to get good at. Karthus primarily deals magic damage (91% of his total damage). He doesn't deal a lot of other damage types and should not be considered a hybrid damage dealer..
Karthus deals a great deal of damage in a regular ranked match (31.095 damage). You should focus on building him as a powerful champ to destroy your foes.
If you are looking for a dominating damage dealer, then you should definitely consider this champ. He has one of the absolute best kill counts in the game amongst all champs. Moreover, he has a somewhat above average death total with an average of 7.4 deaths per League of Legends match. Additionally, Karthus's KDA is typically average with an average KDA ratio of 2.2 as well as 9.6 assists per round.