Matchup

Heavy AP damageCountered by stasisSustained DPSHigh burst

You are stronger early — look to snowball before your opponent scales.

Build vs Karthus

Build adapted to this matchup

Starting items

Doran's Blade
Health Potion

Core build

Profane Hydra
1vs Tank
The Collector
2vs Tank
Infinity Edge
3DPS

Standard

Berserker's Greaves
4AS
Phantom Dancer
5DPS

Summoner spells

41475%
4619%

Anti AD

Plated Steelcaps
4vs AD
Guardian Angel
5vs AD

Anti AP

Mercury's Treads
4vs CC
Mercurial Scimitar
5vs AP

Anti Tank

Lord Dominik's Regards
5vs Tank

DPS

Phantom Dancer
DPS
Ravenous Hydra
DPS
Essence Reaver
DPS
Endless Hunger
DPS
Blade of The Ruined King
DPS
Navori Flickerblade
DPS
100.0% WR2 games
DominationDomination
Hail of BladesHail of Blades
Sudden ImpactSudden Impact
Grisly MementosGrisly Mementos
Treasure HunterTreasure Hunter
PrecisionPrecision
Last StandLast Stand
Legend: AlacrityLegend: Alacrity
Adaptive ForceAdaptive ForceHealth

Power Spikes

Strength by game phase

Early (0-15)
Mid (15-30)
Late (30+)
TryndamereTryndamere
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