Try to knock enemies back into your towers with Explosive Cask.
Try to combo Body Slam with Explosive Cask to set up kills for your team.
The damage reduction from Drunken Rage is applied when you start drinking, try to use it when you see damage coming your way.
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 show some vital Gragas versus Karthus counter statistics that can help us figure out the differences and similarities between this pair of champs. For instance, Gragas’s KDA ratio ([kills + assists] / deaths) of NaN is better than Karthus’s ratio of NaN, showing that Gragas may be more central to his team's team fighting effectiveness than Karthus..
Gragas normally has a similar longest killing spree as his counter does. On average, he takes a similar amount of damage to Karthus. This typically indicates different amounts of tankyness; however, it can also indicate that the champ with increased health has less agility and thus is not able to flee from further damage when engaged or poked.
Both LoL champs are great. Both have their strengths, weaknesses, and counters. In League's current meta, Gragas usually wins when facing off against Karthus, with a 52.5% win rate. Thus, Gragas makes a good counter to Karthus.
While Gragas does have a higher win rate compared to Karthus, when they face off with one another, Gragas also has a lower learning curve that makes him a less complex champion to develop with. You should be be fine when picking Gragas into Karthus.
Additionally, Gragas also has a good 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 isn't a single best champion in League of Legends, in Gragas vs Karthus matchups, Gragas 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 late stage team fights.
Gragas is an above average counter to Karthus. Focus your gameplay on increasing your CS and clearing objectives. If you are able to do that, you should be able to stand on your own as Gragas against Karthus.
If you would like to truly master Gragas to counter Karthus during both the laning 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 mind the build and suggestions presented above, you will increase your win rate significantly and be closer to League of Legends pro players.
Gragas typically racks up a similar amount of CS relative to Karthus. Champions who typically don't get many minion kills typically don't need much CS to be effective, such as support champions. They are able to scale well off of their abilities and first items alone. Yet, champs with a lot of CS, such as hyper-carries, usually have to have many items to be effective. In either situation, try to surpass the values shown here to do well.
The ideal items to focus on in your Gragas versus Karthus build consist of Rabadon's Deathcap, Shadowflame, and Stormsurge. When Gragas incorporated at least these three items in his build, he did a lot better countering Karthus than with most other commonly used counter builds. In fact, Gragas boasted an average win rate of 52.5% when countering Karthus with these items in his kit.
To have the greatest chance of annihilating Karthus as Gragas, you should take the Phase Rush, Manaflow Band, Transcendence, Scorch, Biscuit Delivery, and Cosmic Insight runes from the Sorcery and Inspiration rune sets. Of all the rune sets players chose for Gragas vs Karthus counterpicks, this blending of runes resulted in the best win rate. Notably, these runes provided a 52.5% win rate overall.
If you want to view Gragas vs Karthus tips and counter builds for a an individual division, please choose one from the selection menu shown above. If viewing for the first time, the stats and guides given are computed using all rounds completed with both champs.