You can use Comet of Legend's flight to grow Starsurge to massive proportions.
Comet of Legend allows you to move quickly around the map; use it to put pressure on other lanes.
Save Voice of Light to use as a defense against melee opponents if you need to - otherwise, use its slow to start a fight at long range.
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 stats provided here show some valuable Aurelion Sol against Karthus counter stats that can help us appreciate the differences between the pair. Aurelion Sol’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Karthus’s KDA ratio of NaN, highlighting that Aurelion Sol may be more central to his team's team fighting capability than Karthus..
Aurelion Sol normally has a slightly smaller longest killing spree than his opponent does. Commonly, he takes a similar amount of damage to Karthus. This often reflects differing health capacities, but it can also imply that the one champion has less mobility and thus is not able to kite away from additional damage when engaged or poked.
Both League of Legends champs are great champions. Both have their pros and cons. In League's current meta, Aurelion Sol usually loses when taking on Karthus, with a 48.1% win rate. As a result, Aurelion Sol makes a bad counter to Karthus.
While Aurelion Sol does have a lower winrate than Karthus, when they face off with one another, Aurelion Sol also has a greater difficulty level that makes him a more complex champ to pick up and master. You should be careful when picking Aurelion Sol into Karthusas his relative depth means you may not be able to reach his full potential without a lot of practice beforehand.
Additionally, Aurelion Sol has only a small amount of utility and CC, a similar amount to Karthus. This makes her just as valuable during teamfights, especially when facing champions with a lot of burst damage.
While there is not one best champion in League of Legends, in Aurelion Sol vs Karthus matchups, Karthus is the better champion with a lower win rate, similar champion depth, and a similar amount of utility to help out your allied champions during team fights.
Aurelion Sol is a somewhat poor counter for Karthus. Make sure you focus your actions on maximizing your gold income and destroying objectives. If you can do that, you should do very well as Aurelion Sol against Karthus.
If you would like to truly master Aurelion Sol in order to counter Karthus during both the laning and mid / late game phases of League of Legends, you should keep reading to learn a few extra tricks and insights into this matchup. If you pay attention to the build and tips displayed here, you should increase your win rate significantly and be that much closer to League of Legends pro players.
Aurelion Sol on average gets a similar amount of CS as Karthus. Champions who on average don't take much CS often don't require much CS to be valuable teammates, such as supports. These kinds of champions are able to scale properly off of their abilities and first items alone. Yet, champions with large amounts of CS, such as hyper-carries, often have to have several high cost items to be effective. In either situation, try to surpass the values shown here to do well.
The best items to have in your Aurelion Sol versus Karthus build include Liandry's Anguish, Rylai's Crystal Scepter, and Zhonya's Hourglass. When Aurelion Sol incorporated at least these three items in his build, he did a lot better vs Karthus than with most other common counter builds. In fact, Aurelion Sol had an average win rate of 48.1% when countering Karthus with this counter build.
To have the greatest chance of annihilating Karthus as Aurelion Sol, you should use the Electrocute, Taste of Blood, Eyeball Collection, Relentless Hunter, Biscuit Delivery, and Time Warp Tonic runes from the Domination and Inspiration rune sets. Of all the rune combinations players used for Aurelion Sol vs Karthus counterpicks, this composite of runes resulted in the greatest win rate. In fact, these runes gave a 48.1% winrate overall.
By default, tips, statistics, and builds on how to beat Karthus as Aurelion Sol are presented for all skill levels combined. If you want to scope the stats and builds to an individual skill level, you may use the selection menu earlier in the counter matchup guide.