Vessel
Tentacles are an immense source of power. Don't fight without them.
Spirits inherit their target's current health. If making a
is your goal, try whittling your opponent's health down a bit first to make killing the spirit easier.
Leap of Faith is best used to follow-up a strong engage or when being engaged upon. Be careful about being the first one into a fight.
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 clarify several valuable Illaoi vs. Karthus matchup statistics that may help us realize the differences and similarities between the two. For instance, Illaoi’s KDA ratio ([kills + assists] / deaths) of NaN is more than Karthus’s KDA ratio of NaN, indicating that Illaoi may be more central to her team's team fighting capability than Karthus..
Illaoi normally has a slightly smaller longest kill spree than her matchup does. On average, she receives more damage than Karthus. This commonly reflects differing health capacities, but it can also indicate that the one champ has less agility and thus is not able to kite away from further damage when engaged or poked.
Both League champions are great. Both have their pros and cons. In League's current meta, Illaoi usually fairs equally well when taking on Karthus, with a 49.5% win rate. As a result, Illaoi makes an ok counter to Karthus.
While Illaoi does have a lower win rate than Karthus, when facing one another, Illaoi also has a lower level of difficulty that makes her a less difficult champ to pick up and master. You still need to be cautious when picking Illaoi into Karthus.
Moreover, Illaoi has only a small amount of CC and other utility, a similar amount to Karthus. This makes her just as valuable during teamfights, especially when fighting champions with a ton of burst damage.
While there isn't a single best champion overall in League of Legends, in Illaoi vs Karthus matchups, Karthus 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.
Illaoi is a somewhat poor counter for Karthus. You will do well by focussing your gameplay on increasing your CS and destroying objectives. If you can do that, you should be able to stand on your own as Illaoi against Karthus.
To truly master Illaoi in order to counter Karthus during both the laning and mid / late game phases of League of Legends, you should keep reading to pick up a few extra tricks and insights into this matchup. If you pay attention to the build and tips shown above, you should increase your win rate significantly and be that much closer to League of Legends pro players.
Illaoi on average gets more CS compared to Karthus. Champions who on average don't take many minion kills often don't require much CS to be valuable teammates, such as sup champs. These kinds of champions are capable of scaling properly off of their abilities and first items alone. Yet, champions with large amounts of CS, such as hyper-carries, typically need many items to be effective. In either case, try to surpass the values reported on this page to do well.
The most important items to have in your Illaoi versus Karthus build consist of Sterak's Gage, Spirit Visage, and Iceborn Gauntlet. When Illaoi used at least these three items in her build, she performed significantly better vs Karthus than with most other typical item sets. In fact, Illaoi had an average win rate of 49.5% when countering Karthus with these items in her kit.
To have the highest probability of beating Karthus as Illaoi, Illaoi players should take the Grasp of the Undying, Demolish, Bone Plating, Overgrowth, Last Stand, and Presence of Mind runes from the Resolve and Precision rune sets. Of all the runes players picked for Illaoi vs Karthus counters, this blending of runes resulted in the best win rate. Notably, these runes provided a 49.5% winrate overall.
By default, tips, statistics, and builds on how to beat Karthus as Illaoi are displayed for every ranked division. If you would like to narrow the statistics and builds to a particular skill level, you can use the selection menu located above.