This will vary because unlike other stat sites we include 100% of a brackets champions played and never include champions that don't belong in the bracket.
Emerald+ Champions Analysed: 25,612,396
We include 100% of the champions played of every selected tier bracket in our analysis, we never include champions from outside the tier quoted tier.
Karthus Counters
Karthus top vs support Counters
Presently there is insufficent games played by Karthus top on Patch 14.18 to determine the strongest support counters. A matchup requires a minimum of 100 games to be displayed.
Senna
the Redeemer
Karthus wins against Senna 39.62% of the time which is 7.02% lower against Senna than the average opponent.
After normalising both champions win rates Karthus wins against Senna 8.45% less often than would be expected.
The average opponent winrate against Sennais 46.64%.
Thresh
the Chain Warden
Karthus wins against Thresh 56.03% of the time which is 7.23% higher against Thresh than the average opponent.
After normalising both champions win rates Karthus wins against Thresh 5.80% more often than would be expected.
The average opponent winrate against Threshis 48.80%.
Lulu
the Fae Sorceress
Karthus wins against Lulu 56.19% of the time which is 8.76% higher against Lulu than the average opponent.
After normalising both champions win rates Karthus wins against Lulu 7.33% more often than would be expected.
The average opponent winrate against Luluis 47.43%.