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 some valuable Volibear against Karthus counter statistics that can help you grasp the differences between these two champs. As an example, Volibear’s KDA ratio ([kills + assists] / deaths) of NaN is greater than Karthus’s ratio of NaN, highlighting that Volibear may be more central to his team's team fighting potential than Karthus..
Volibear usually has a similar longest kill spree as his matchup does. Typically, he takes more damage than Karthus. This typically indicates differing health capacities; however, it can also indicate that the champ with increased HP has less mobility and thus is unable to escape additional harm when engaged or poked.
Both League champions are great. Both champs have their strengths, weaknesses, and counters. In the game's current meta, Volibear usually wins when playing against Karthus, with a 51.7% win rate. As a result, Volibear makes a good counter to Karthus.
While Volibear does have a higher win rate than Karthus, when on opposite teams, Volibear also has a much lower difficulty level that makes him a less challenging champion to learn and master. You should be careful when picking Volibear into Karthus.
Additionally, Volibear has some amount of CC and other utility, a similar amount to Karthus. This often makes her just as valuable during teamfights, especially when facing champions with a ton of burst damage.
While there isn't a single best champion for every situation in League of Legends, in Volibear vs Karthus matchups, Volibear is the better champ with a higher win rate, less champion complexity, and a similar amount of utility to help out your allied champions during team fights.
Volibear is a decent counter to Karthus. You will do well by focussing your play on maximizing your gold and cs and taking out objectives. If you are able to do that, you should hold your own as Volibear against Karthus.
If you would like to truly master Volibear in order to counter Karthus during both the laning and mid / late game phases of League of Legends, you should continue reading to gather a few extra tricks and insights into this matchup. If you listen to the build and suggestions shown above, you will increase your win rate significantly and be that much closer to League of Legends pro players.
Volibear typically racks up more CS relative to Karthus. Champions who typically don't acquire much CS often don't have to have much CS to be valuable teammates, such as sup champs. These kinds of champions are capable of scaling well off of their skills, stats, and first items alone. Yet, champs with large amounts of CS, such as hyper-carries, typically need several high cost items to be effective. In either case, try to do better than the numbers reported here to do well.
The top items to use in your Volibear versus Karthus build consist of Nashor's Tooth, Hullbreaker, and Riftmaker. When Volibear combined at least these three items in his build, he performed a lot better versus Karthus than with most other commonly used counter builds. In fact, Volibear had an average win rate of 51.7% when playing against Karthus with these items in his kit.
To have the best likelihood of annihilating Karthus as Volibear, you should take the Lethal Tempo, Triumph, Legend: Alacrity, Last Stand, Demolish, and Revitalize runes from the Precision and Resolve rune sets. Of all the runes players chose for Volibear vs Karthus battles, this blending of runes yielded the best win rate. In fact, these runes averaged a 51.7% win rate overall.
By default, tips, statistics, and builds on how to beat Karthus as Volibear are displayed for all ranked divisions combined. If you would like to scope the stats and builds to a particular division, you can use the selection menu located earlier in the counter matchup guide.