Make sure you choose the right augment at the right time.
Death Ray is a powerful poke and a strong area of denial tool. Use it in combination with Gravity Field to control your enemy's position.
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 underscore several significant Viktor versus Karthus counter statistics that can help you figure out the differences between the pair. Viktor’s KDA ratio ([kills + assists] / deaths) of NaN is better than Karthus’s KDA ratio of NaN, highlighting that Viktor may be more central to his team's team fighting effectiveness than Karthus..
Viktor normally has a similar longest kill spree as his foe does. Commonly, he receives less damage than Karthus. This often reflects differing health capacities, yet it can also illustrate that the one champ has less agility and thus is not able to kite away from additional damage when poked or engaged.
Both League champs are great. Both champs have their strengths, weaknesses, and counters. In the game's current meta, Viktor usually wins when facing off against Karthus, with a 53.8% win rate. Thus, Viktor makes a great counter to Karthus.
While Viktor does have a higher winrate than Karthus, when facing one another, Viktor also has a greater learning curve that makes him a more challenging champion to develop with. You should be be fine when picking Viktor into Karthusas his relative depth means you may not be able to reach his full potential without a significant amount of practice beforehand.
Furthermore, Viktor also has almost no amount of utility and CC, a similar amount to Karthus. This makes her just as valuable during team fights, especially when fighting champions with a ton of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Viktor vs Karthus matchups, Viktor is the better champ with a noticably higher win rate, more champion depth, and a similar amount of utility to help out your teammates during late stage team fights.
Viktor is a great counter for Karthus. Make sure you focus your tactics on maximizing your gold and cs and taking out objectives. If you can do that, you should be able to stand on your own as Viktor against Karthus.
If you would like to learn all of the intricacies of Viktor to counter Karthus during both the lane and mid / late game phases of League of Legends, you should continue reading to learn a few extra tricks and insights into this matchup. If you pay attention to the build and stats presented here, you will grow your win rate by a lot and be closer to League of Legends pro players.
Viktor typically racks up more CS compared to Karthus. Champions who typically don't earn much CS typically don't have to have much CS to be valuable teammates, such as supports. They are able to scale properly off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, usually need a lot of items to be effective. In either case, try to surpass the numbers reported on this page to do well.
The top items to focus on in your Viktor versus Karthus build consist of Rabadon's Deathcap, Shadowflame, and Luden's Companion. When Viktor incorporated at least these three items in his build, he did significantly better countering Karthus than with most other commonly used builds. In fact, Viktor boasted an average win rate of 53.8% battling Karthus with this build.
To have the best chance of crushing Karthus as Viktor, you should take the First Strike, Magical Footwear, Biscuit Delivery, Cosmic Insight, Manaflow Band, and Transcendence runes from the Inspiration and Sorcery rune sets. Of all the rune builds players chose for Viktor vs Karthus battles, this combo of runes resulted in the best win rate. Notably, these runes averaged a 53.8% win rate overall.
By default, tips, statistics, and builds on how to beat Karthus as Viktor are given for all skill levels, merged. If you want to narrow the stats and builds to a distinct player tier, you should use the selection menu at the top of this page.