You can set her passive to use hotkeys in the options menu. The default is Shift+F1~F5
Try to use Inherent Glamour sparingly, ineffective uses will put enemies on the alert.
Karthus can cast spells for a short duration after he is killed. Move away from his corpse to be safe.
Make sure you always have enough health to survive Requiem, even if you have to go back to the base more frequently to heal.
The stat comparisons shown on this page emphasize some strategic Neeko against Karthus matchup statistics that can help us understand the distinctions between the two. As an example, Neeko’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Karthus’s KDA ratio of NaN, showing that Neeko may be more central to her team's team fighting effectiveness than Karthus..
Neeko typically has a slightly smaller longest killing spree than her counter does. On average, she takes less damage than Karthus. This commonly reflects differing health capacities, but it can also imply that the champion with more health has less agility and thus is not able to kite away from further damage when poked or engaged.
Both LoL champs are great champions. Both champs have their pros and cons. In League's current meta, Neeko usually fairs equally well when playing against Karthus, with a 50.5% win rate. Therefore, Neeko makes an ok counter for Karthus.
While Neeko does have a higher win rate than Karthus, when facing one another, Neeko also has a lower difficulty level that makes her a less difficult champion to learn. You should be careful when picking Neeko into Karthus.
Furthermore, Neeko has some amount of CC and other utility, a similar amount to Karthus. This often makes her just as valuable during teamfights, especially when trying to counter champions with a lot of burst damage.
While there isn't one best champion in League of Legends, in Neeko vs Karthus matchups, Neeko is the better champ with a similar win rate, less champion complexity, and a similar amount of utility to help out your teammates during team fights.
Neeko is a decent counter for Karthus. Make sure you focus your play on increasing your gold and cs and clearing objectives. If you are able to do that, you should do very well as Neeko against Karthus.
If you would like to truly master Neeko to counter Karthus during both the early game and mid / late game phases of League of Legends, you should continue reading to learn a few extra tricks and insights into this matchup. If you pay attention to the build and tips presented here, you should increase your win rate significantly and be that much closer to League of Legends pro players.
Neeko often accumulates a similar amount of CS relative to Karthus. Champions who typically don't get many minion kills usualy don't require much CS to be valuable teammates, such as sup champs. They are able to scale properly off of their skills, stats, and first items alone. Yet, champs with large amounts of CS, such as hyper-carries, often need several high cost items to be effective. In either case, try to exceed the values displayed on this page to do well.
The top items to use in your Neeko versus Karthus build include Hextech Rocketbelt, Zhonya's Hourglass, and Zaz'Zak's Realmspike. When Neeko incorporated at least these three items in her build, she did much better versus Karthus than with most other typical builds. In fact, Neeko boasted an average winrate of 50.5% when countering Karthus with these items in her kit.
To have the greatest probability of coming out on top against Karthus as Neeko, Neeko players should use the Arcane Comet, Manaflow Band, Transcendence, Scorch, Biscuit Delivery, and Cosmic Insight runes from the Sorcery and Inspiration rune sets. Out of all the runes players picked for Neeko vs Karthus battles, this mixture of runes yielded the best win rate. Notably, these runes averaged a 50.5% winrate overall.
If you would like to see Neeko x Karthus tips and counter builds for a an individual rank, feel free to select one from the selection menu displayed above. At first, the statistics and build suggestions shown are computed using every game with data with both champs.