Matchup

Heavy AP damageCountered by stasisSustained DPSHigh burst

Build vs Karthus

Build adapted to this matchup

Starting items

Health Potion
x2

Core build

Ardent Censer
1
Shurelya's Battlesong
2
Redemption
3

Standard

Ionian Boots of Lucidity
4CDR
Dream Maker
5HP

Summoner spells

4781%
3413%

Anti AD

Plated Steelcaps
4vs AD
Jak'Sho, The Protean
5vs Hybride

Anti CC

Mercury's Treads
4vs CC

Other options

Dream Maker
HP
Moonstone Renewer
HP
Mikael's Blessing
HP
Locket of the Iron Solari
HP
Oblivion Orb
Echoes of Helia
HP
100.0% WR1 games
SorcerySorcery
Summon AerySummon Aery
Manaflow BandManaflow Band
TranscendenceTranscendence
ScorchScorch
ResolveResolve
RevitalizeRevitalize
Bone PlatingBone Plating
Ability HasteAdaptive ForceHealth Scaling

Power Spikes

Strength by game phase

Early (0-15)
Mid (15-30)
Late (30+)
LuluLulu
KarthusKarthus
Neutral
Neutral
Neutral

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