Matchup
Heavy AP damageCountered by stasisSustained DPSHigh burst
Build vs Karthus
Build adapted to this matchup
Starting items
Core build
Standard
Summoner spells
50%
50%Anti Tank
DPS
100.0% WR1 games
Precision
Conqueror
Presence of Mind
Legend: Haste
Last Stand
Resolve
Unflinching
Second Wind
Power Spikes
Strength by game phase
Early (0-15)
Mid (15-30)
Late (30+)
Sylas
KarthusAggressive
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
| Level | Q | W | E | R |
|---|---|---|---|---|
| 3 | 0s | 15s | 0.5s | – |
| 6 | 0s | 15s | 0.5s | 3m20 |
| 9 | 0s | 15s | 0.5s | 3m20 |
| 11 | 0s | 15s | 0.5s | 3m |
| 16 | 0s | 15s | 0.5s | 2m40 |
| 18 | 0s | 15s | 0.5s | 2m40 |
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