How to win lane as Karthus against Kai'Sa · 53.56% win rate (3,204 Emerald+ games, lolalytics, sampled July 2026) · Matchup data reviewed on patch 26.15
Her stream needs range your aura taxes and time your Requiem bills — iso-Q the lane and collect globally.
Track: Kai'Sa's E — Supercharge (16–10s cooldown). Her reposition + stealth window — engage in the sixteen seconds after she burns it.
Read from Karthus's seat: which stage windows this plan plays for against Kai'Sa.
| Stage | Favoured | Why |
|---|---|---|
| Level 1 | Karthus | Before her Plasma stacks, Kai'Sa can't contest your level 1 Lay Waste poke. |
| Level 2 | Karthus | At level 2 you still out-range her without W online. |
| Level 3 | Kai'Sa | Level 3 W plus a full Plasma proc lets Kai'Sa burst and out-trade you. |
| Levels 4-5 | Karthus | By levels 4-5 your Requiem threat and poke recovery swing it back to you. |
| Level 6 | Karthus | Level 6 Requiem out-classes her reposition ult by executing low Plasma trades. |
| First item | Karthus | Your first AP item out-pokes her before she completes R-engage items. |
| Two+ items | Karthus | With two items Requiem snipes her out of dives, out-scaling her mobility. |
Levels 1-2 are yours: before Kai'Sa's Plasma stacking and W come online she can't trade into your Lay Waste range, so you poke and farm freely. She is farming quietly toward an item threshold, so contesting the wave with Lay Waste costs her more than any chip you land on her. Cast at the minions she needs. Keep the wall for her support, because on her own she has nothing that reaches you before her first evolve.
Pooled Emerald+ win rates from Karthus's side, sampled July 2026.
The full Karthus vs Kai'Sa report continues with the mid-game plan, the late-game and teamfight plan, every power spike to play around, and the win conditions for both sides — plus cooldown tracking and the live enemy-jungle tracker inside the app.
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Karthus, slightly — a 53.56% win rate edge over 3,204 games; execution can flip it.
Mostly — Karthus has a small statistical edge (53.56% win rate), but execution decides this lane far more than the pick does.
Not a hard counter — Karthus has a slight edge (53.56% win rate), and play quality decides the rest.
Karthus takes Dark Harvest on the Domination tree with Cheap Shot, Grisly Mementos and Ultimate Hunter, and Sorcery secondary (Manaflow Band and Transcendence) vs Kai'Sa.
Start Doran's Ring + 2 Health Potions and back for Lost Chapter (≈1300g). Build Liandry's / Blackfire first, then Rabadon's path, with Sorcerer's Shoes.
Playing the other side? Kai'Sa vs Karthus guide →
All Karthus bot lane matchups →
More Karthus bot lane matchups: vs Heimerdinger · vs Jhin · vs Jinx · vs Kalista · vs Kog'Maw · vs Lucian