Lay Waste is very strong at farming minions and harassing enemy champions.
Ask your allies to help point out when you should use Requiem to get kills in different lanes.
Aqua Prison is a very powerful ability with a long cooldown, take advantage of the situation if Nami misses this ability.
Tidal Wave has a very long range but travels slowly, be aware of when it is coming your way as you can move out of its path.
Try to avoid fighting an opponent affected by Tidecaller's Blessing, it lasts a short duration so waiting it out can help you greatly.
The stat comparisons provided here clarify some critical Karthus versus Nami counter stats that can help us explain the distinctions between this pair of champs. As an example, Karthus’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Nami’s ratio of NaN, demonstrating that Karthus may be more central to his team's team fighting effectiveness than Nami. This observation is in large part caused by the difference in kills.
Karthus often has a much larger longest kill spree than his opponent does. On average, he takes more damage than Nami. This often reflects differing health capacities, but it can also imply that the one champion has less mobility and thus is not able to escape further damage when engaged or poked.
Both League champs are great champions. Both champs have their strengths, weaknesses, and counters. In League's current meta, Karthus usually fairs equally well when taking on Nami, with a 50.8% win rate. Thus, Karthus makes an ok counter for Nami.
While Karthus does have a higher winrate than Nami, when facing one another, Karthus also has a greater level of difficulty that makes him a more difficult character to develop with. You still need to be cautious when picking Karthus into Namias his relative depth means you may not be able to reach his full potential without a significant amount of practice beforehand.
Furthermore, Karthus also has some amount of CC and other utility, a similar amount to Nami. This often makes her just as valuable during teamfights, especially when fighting champions with a lot of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Karthus vs Nami matchups, Karthus is the better champion with a similar win rate, more champion depth, and a similar amount of utility to help out your team members during late stage team fights.
Karthus is a decent counter to Nami. Make sure you focus your gameplay on increasing your gold and cs and taking out objectives. If you do that, you should be able to stand on your own as Karthus against Nami.
To learn all of the intricacies of Karthus to counter Nami during both the early game and mid / late game phases of League of Legends, you should keep reading to learn a few extra tips and tricks for this matchup. If you pay attention to the build and tips shown above, you will increase your win rate by a lot and be that much closer to League of Legends pro players.
Karthus most often racks up much more CS compared to Nami. Champs who typically don't acquire many minion kills often don't need much CS to be valuable teammates, such as support champions. These kinds of champions are able to scale well off of their abilities and first items alone. Yet, champions with large amounts of CS, such as hyper-carries, typically have to have many items to be effective. In either case, try to surpass the values shown here to do well.
The top items to prioritize in your Karthus versus Nami build consist of Malignance, Shadowflame, and Stormsurge. When Karthus combined at least these three pieces in his build, he did significantly better vs Nami than with most other common builds. In fact, Karthus boasted an average win rate of 50.8% when playing against Nami with this build.
To have the highest likelihood of crushing Nami as Karthus, you should equip the Dark Harvest, Cheap Shot, Eyeball Collection, Ultimate Hunter, Gathering Storm, and Transcendence runes from the Domination and Sorcery rune sets. Out of all the rune builds players used for Karthus vs Nami clashes, this sequence of runes yielded the best win rate. In fact, these runes gave a 50.8% winrate overall.
If you need to see Karthus x Nami tips and builds for a a specific division rank, feel free to choose one from the selection menu displayed above. If viewing for the first time, the statistics and strategies displayed are computed using all matches completed with both champions.