Matchup

Heavy AP damageCountered by stasisSustained DPSHigh burst

Build vs Karthus

Build adapted to this matchup

Starting items

Doran's Blade
Health Potion

Core build

Eclipse
1DPS
Spear of Shojin
2Bruiser
Sterak's Gage
3Survival

Standard

Boots of Swiftness
4vs Slow
Black Cleaver
5vs Tank

Summoner spells

41477%
41219%

Anti AD

Plated Steelcaps
4vs AD
Death's Dance
5vs AD
Guardian Angel
vs AD
Dead Man's Plate
vs AD
Randuin's Omen
vs AD

Anti AP

Mercury's Treads
4vs CC
Maw of Malmortius
5vs AP
Spirit Visage
vs AP

Anti Tank

Black Cleaver
5vs Tank
Voltaic Cyclosword
vs Tank

DPS

Stridebreaker
Bruiser
100.0% WR3 games
PrecisionPrecision
ConquerorConqueror
TriumphTriumph
Legend: AlacrityLegend: Alacrity
Last StandLast Stand
ResolveResolve
UnflinchingUnflinching
Bone PlatingBone Plating
Adaptive ForceAdaptive ForceHealth Scaling

Power Spikes

Strength by game phase

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