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

Essence Reaver
1DPS
Spear of Shojin
2Bruiser
Black Cleaver
3vs Tank

Standard

Boots of Swiftness
4vs Slow
Rapid Firecannon
5DPS

Summoner spells

41284%
42111%

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

Rapid Firecannon
DPS
Endless Hunger
DPS
Infinity Edge
DPS
100.0% WR2 games
SorcerySorcery
Deathfire TouchDeathfire Touch
Nimbus CloakNimbus Cloak
CelerityCelerity
Gathering StormGathering Storm
InspirationInspiration
Magical FootwearMagical Footwear
Jack Of All TradesJack Of All Trades
Adaptive ForceMove SpeedHealth Scaling

Power Spikes

Strength by game phase

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