MacroMind matchup data: real ranked games, not opinions
Karthus vs Jax
Karthus vs Jax in Jungle: who wins more often?
Across 190 ranked games in Jungle, Karthus beats Jax in 52% of them.
Global ranked sample: games from every region and every rank pooled together, not one server's stats. Data runs through patch 26.12; curves updated 2026-08-07.
By 15 minutes the median game has Karthus ahead by 530 gold.
Karthus at 15:00
- Gold: +530
- CS: +21
- XP: +908
Typical gap to Jax, from 190 games that reached 15:00.
Does Karthus counter Jax?
Even on the count: Karthus lands at 52% over 190 games. Neither pick wins the lane alone, so take the side you play better and use the rows below to see which early spots swing this one, then play your first ten minutes around them.
Your Karthus game plan against Jax
With a gold lead at 10:00, Karthus wins 58% of 128 games in this matchup. Behind at the same mark, the rate drops to 39% over 62.
| The spot | Win rate | Games |
|---|---|---|
| Ahead in gold at 10:00 | 58% | 128 |
| Behind in gold at 10:00 | 39% | 62 |
| First blood | 57% | 84 |
| +kills at 10:00 | 65% | 74 |
| +CS at 10:00 | 55% | 152 |
In the median game here, the first death comes near 5:06 and level 6 lands around 6:40. Until your spike is online, treat the all-in window with respect.
Karthus in Jungle: the items that actually get built
Into Jax specifically, Karthus finishes Blackfire Torch first most often: 51.7% over 60 games of this matchup.
The most-finished Karthus core is Blackfire Torch, Shadowflame, Rabadon's Deathcap: 53.6% across 1,882 games when all three got done. All matchups, patches 26.1-26.12.
Most games start Scorchclaw Pup + Health Potion; the first finished item is usually Blackfire Torch (8,818 games).
Skill plan: Karthus players max Q first and take Q at level 1.