MacroMind matchup data — real ranked games, not opinions
Jayce vs Karthus
How often does Jayce beat Karthus in Jungle?
Jayce into Karthus in Jungle: 46% observed win rate across 427 ranked games. Counted from real matches, and every number here shows its sample size.
By 15 minutes the median game has Jayce ahead by 20 gold.
Does Jayce counter Karthus?
Too close for a counter call: Jayce sits at 46% over 427 games, inside the noise band. On this sample neither pick counters the other — the swing lives in the conditions below, so play the side you know better.
Beating Karthus: the Jayce game plan
A 300-gold lead at 10:00 puts Jayce at 53% across 224 games. Flip the lead and Jayce falls to 39% across 203.
| The spot | Win rate | Games |
|---|---|---|
| 300 gold up at 10:00 | 53% | 224 |
| 300 gold down at 10:00 | 39% | 203 |
| First blood | 50% | 266 |
| +kills at 10:00 | 54% | 181 |
| +CS at 10:00 | 57% | 135 |
| 0 deaths at 10:00 | 57% | 98 |
Someone usually dies here around 6:02 in the median game, and level 6 lands near 6:55. Until your spike is online, respect the all-in.
Jayce's Jungle build, with receipts
Into Karthus specifically, Jayce finishes Youmuu's Ghostblade first most often: 42.2% over 187 games of this matchup.
The most-finished core in this exact matchup is Youmuu's Ghostblade, Opportunity, Edge of Night: 44.1% across 59 games.
The most-finished Jayce core is Youmuu's Ghostblade, Opportunity, Edge of Night: 52.3% across 3,541 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 Youmuu's Ghostblade (14,088 games).
Skill plan: Jayce players max Q first and take Q at level 1.