Consider when to cast Lunar Rush without Moonlight and when to wait for another Crescent Strike.
Landing Crescent Strike is critically important, but don't be afraid to miss. The cooldown is short and the mana cost is low.
Use Moonfall and Lunar Rush to stay on targets and activate Moonsilver Blade for extra damage.
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 here highlight several critical Diana against Karthus matchup stats that can help us appreciate the differences between the pair. Diana’s KDA ratio ([kills + assists] / deaths) of NaN is better than Karthus’s ratio of NaN, demonstrating that Diana may be more central to her team's team fighting capability than Karthus..
Diana usually has a similar longest kill spree as her foe does. Typically, she takes more damage than Karthus. This often reflects different amounts of tankyness, but it can also illustrate that the champion with increased HP has less agility and thus is unable to escape further harm when engaged or poked.
Both League of Legends champs are great. Both champs have their strengths, weaknesses, and counters. In League's current meta, Diana usually wins when playing against Karthus, with a 53.4% win rate. As a result, Diana makes a great counter to Karthus.
While Diana does have a higher winrate compared to Karthus, when facing one another, Diana also has a lower learning curve that makes her a less challenging champ to learn and master. You don't need to be too worried when picking Diana into Karthus.
Moreover, Diana also has almost no amount of CC and other utility, a similar amount to Karthus. This often makes her just as valuable during teamfights, especially when facing champions with a lot of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Diana vs Karthus matchups, Diana is the better champ with a noticably higher win rate, less champion complexity, and a similar amount of utility to help out your teammates during team fights.
Diana is a great counter for Karthus. You will do well by focussing your gameplay on keeping up your gold income and destroying objectives. If you are able to do that, you should do very well as Diana against Karthus.
If you would like to learn all of the intricacies of Diana to counter Karthus during both the laning and mid / late game phases of League of Legends, you should continue reading to pick up a few extra lessons on this matchup. If you mind the build and tips displayed here, you will grow your win rate by a lot and be that much closer to League of Legends pro players.
Diana on average gets less CS relative to Karthus. Champs who on average don't acquire many minion kills typically don't have to have much CS to be valuable teammates, such as sup champs. They are able to scale well off of their skills, stats, and first items alone. Yet, champs with large amounts of CS, such as hyper-carries, typically require many items to be effective. In either case, try to do better than the numbers reported here to do well.
The top items to have in your Diana versus Karthus build include Hextech Rocketbelt, Rabadon's Deathcap, and Zhonya's Hourglass. When Diana combined at least these three pieces in her build, she performed significantly better when facing Karthus than with many other typical counter builds. In fact, Diana had an average win rate of 53.4% when countering Karthus with these items in her kit.
To have the highest chance of coming out on top against Karthus as Diana, you should equip the Conqueror, Triumph, Legend: Alacrity, Last Stand, Magical Footwear, and Cosmic Insight runes from the Precision and Inspiration rune sets. Of all the rune sets players picked for Diana vs Karthus fights, this order of runes resulted in the greatest win rate. In fact, these runes averaged a 53.4% winrate overall.
By default, tips, stats, and builds on how to beat Karthus as Diana are presented for every ranked division. If you want to scope the statistics and builds to a specific rank, you can use the selection menu earlier in the counter matchup guide.