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

Stridebreaker
1Bruiser
Experimental Hexplate
2Bruiser
Fiendhunter Bolts
3DPS

Standard

Boots of Swiftness
4vs Slow
Maw of Malmortius
5vs AP

Summoner spells

4685%
4127%

Anti AD

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

Anti AP

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

DPS

Ravenous Hydra
DPS
Sundered Sky
Bruiser
Infinity Edge
DPS
Phantom Dancer
DPS

Other options

Sterak's Gage
Survival
Overlord's Bloodmail
HP
100.0% WR2 games
PrecisionPrecision
ConquerorConqueror
TriumphTriumph
Legend: AlacrityLegend: Alacrity
Last StandLast Stand
InspirationInspiration
Biscuit DeliveryBiscuit Delivery
Approach VelocityApproach Velocity
Attack SpeedAdaptive ForceHealth Scaling

Power Spikes

Strength by game phase

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