For increased range and damage, try casting Shock Blast through the Acceleration Gate.
If you find yourself taking lots of damage, try using Jayce's Hammer Stance, as it grants you additional defenses.
Be sure to switch stances often. It will enhance your attacks and grant you quick bursts of speed.
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 provided here underscore some valuable Jayce against Karthus matchup statistics that may help us interpret the differences and similarities between the two. As an example, Jayce’s KDA ratio ([kills + assists] / deaths) of NaN is more than Karthus’s ratio of NaN, indicating that Jayce may be more central to his team's team fighting potential than Karthus..
Jayce often has a similar longest kill spree as his enemy does. On average, he receives less damage than Karthus. This often reflects different amounts of tankyness; however, it can also indicate that the one champion has less mobility and thus is unable to escape further harm when poked or engaged.
Both League champs are great champions. Both champs have their pros and cons. In League's current meta, Jayce usually loses when trying to fight Karthus, with a 48.4% win rate. Therefore, Jayce makes a poor counter to Karthus.
While Jayce does have a lower win rate compared to Karthus, when facing one another, Jayce also has a greater learning curve that makes him a more time consuming champ to develop with. You should be careful when picking Jayce into Karthusas his relative depth means that you may not be able to unleash his full potential without a lot of practice beforehand.
Additionally, Jayce 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 trying to counter champions with a ton of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Jayce vs Karthus matchups, Karthus is the better champ with a lower win rate, similar champion depth, and a similar amount of utility to help out your teammates during teamfights.
Jayce is a somewhat poor counter to Karthus. You will do well by focussing your play on maximizing your gold and cs and destroying objectives. If you are able to do that, you should be able to stand on your own as Jayce against Karthus.
If you would like to learn all of the intricacies of Jayce to counter Karthus during both the laning and mid / late game phases of League of Legends, you should keep reading to gather a few extra lessons on this matchup. If you listen to the build and suggestions displayed above, you will increase your win rate significantly and be closer to League of Legends pro players.
Jayce usually accumulates more CS as Karthus. Champs who on average don't take much CS usualy don't need much CS to be valuable teammates, such as support champions. These kinds of champions are capable of scaling well off of their skills, stats, and first items alone. Yet, champions with large amounts of CS, such as hyper-carries, usually need several high cost items to be effective. In either situation, try to surpass the values displayed on this page to do well.
The best items to use in your Jayce versus Karthus build consist of Muramana, Maw of Malmortius, and Serylda's Grudge. When Jayce incorporated at least these three pieces in his build, he did much better against Karthus than with many other commonly used counter builds. In fact, Jayce boasted an average win rate of 48.4% when playing against Karthus with this counter build.
To have the highest probability of vanquishing Karthus as Jayce, you should take the Phase Rush, Manaflow Band, Absolute Focus, Gathering Storm, Biscuit Delivery, and Magical Footwear runes from the Sorcery and Inspiration rune sets. Of all the rune sets that we analyzed for Jayce vs Karthus battles, this set of runes resulted in the highest win rate. Moreover, these runes averaged a 48.4% win rate overall.
If you would like to view Jayce versus Karthus tips and counter stats for a a particular rank, please select one from the selection menu shown above. At first, the statistics and guides displayed are calculated using every round with data with these champs.