Matchup

Heavy AP damageCountered by stasisSustained DPSHigh burst

Build vs Karthus

Build adapted to this matchup

Starting items

Doran's Shield
Health Potion

Core build

Trinity Force
1DPS
Bandlepipes
2vs Hybride
Protoplasm Harness
3Survival

Standard

Boots of Swiftness
4vs Slow
Spirit Visage
5vs AP

Summoner spells

61247%
41241%

Anti AD

Plated Steelcaps
4vs AD
Frozen Heart
5vs AD
Randuin's Omen
vs AD
Dead Man's Plate
vs AD

Anti Heal

Thornmail
6vs Hybride

Anti AP

Mercury's Treads
4vs CC
Spirit Visage
5vs AP
Kaenic Rookern
vs AP
Force of Nature
vs AP

Other options

Jak'Sho, The Protean
vs Hybride
100.0% WR2 games
PrecisionPrecision
Fleet FootworkFleet Footwork
TriumphTriumph
Legend: HasteLegend: Haste
Last StandLast Stand
ResolveResolve
UnflinchingUnflinching
Second WindSecond Wind
Ability HasteHealth ScalingHealth Scaling

Power Spikes

Strength by game phase

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

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