Matchup

Heavy AP damageCountered by stasisSustained DPSHigh burst

You are stronger late game — farm safe and avoid early trades.

Build vs Karthus

Build adapted to this matchup

Starting items

Doran's Blade
Health Potion

Core build

The Collector
1vs Tank
Infinity Edge
2DPS
Lord Dominik's Regards
3vs Tank

Standard

Berserker's Greaves
4AS
Profane Hydra
5vs Tank

Summoner spells

414100%

Anti AD

Plated Steelcaps
4vs AD
Guardian Angel
5vs AD

Anti CC

Mercury's Treads
4vs CC

Anti Tank

Profane Hydra
5vs Tank
Edge of Night
vs Tank
Youmuu's Ghostblade
vs Tank

DPS

Stormrazor
DPS
100.0% WR1 games
DominationDomination
ElectrocuteElectrocute
Sudden ImpactSudden Impact
Grisly MementosGrisly Mementos
Treasure HunterTreasure Hunter
SorcerySorcery
Absolute FocusAbsolute Focus
Gathering StormGathering Storm
Attack SpeedAdaptive ForceHealth Scaling

Power Spikes

Strength by game phase

Early (0-15)
Mid (15-30)
Late (30+)
QuinnQuinn
KarthusKarthus
Aggressive
Careful
Careful

Karthus's abilities

Passive, spells and ultimate

Death Defied (P)

Upon dying, Karthus enters a spirit form that allows him to continue casting spells.

Cooldowns

Cooldowns by spell rank

LevelQWER
30s15s0.5s
60s15s0.5s3m20
90s15s0.5s3m20
110s15s0.5s3m
160s15s0.5s2m40
180s15s0.5s2m40

Playing against Karthus

How to counter and exploit weaknesses

1

Zhonya's, Edge of Night, and Banshee's block/cancel his R — buy one of these items if Karthus focuses you.

2

His Q deals double damage on isolated targets: stay in your minions or near allies to split the damage.

3

Shields, Soraka R, and heals can counter his R if well-timed — save an emergency heal for Requiem.

4

Karthus is immobile and squishy — dive him quickly to eliminate him before he deals continuous damage.

Source: op.gg + LTL Engine · Patch 16.9.1 · May 9, 2026