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. Observed from real matches — the sample size sits next to the rate, here and on every number below.
By 15 minutes the median game has Karthus ahead by 530 gold.
Does Karthus counter Jax?
No counter call here: Karthus lands at 52% over 190 games, inside the noise band for a sample this size. Neither pick wins the lane on its own — the swing lives in the spots below, so take the side you play better and use the receipts.
Your Karthus game plan against Jax
With a 300-gold lead at 10:00, Karthus wins 58% of 128 games in this matchup. Down 300 at the same mark, the rate drops to 39% over 62.
| The spot | Win rate | Games |
|---|---|---|
| 300 gold up at 10:00 | 58% | 128 |
| 300 gold down 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 16.1-16.12.
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.