When Is Karthus Strongest?
This is a late-game profile, strongest with full items online, and games at this rank average around 29 minutes. Karthus wins by scaling into a late-game execute machine, so use the power window to farm safely, then start hunting cross-map kills and turning every low enemy into free damage from the fog.
Karthus Item Build
Karthus is a scaling artillery mage who farms up and then rains global damage on the entire enemy team. The build stacks ability power, mana, and haste so his blasts hit harder, his aura drains without going dry, and his ultimate can execute from anywhere on the map.
Best Karthus Runes
Dark Harvest is the go-to, and his kit feeds it perfectly. His repeated Q casts and his damage toggle keep it working, so his output climbs the longer a fight drags on. Pair it with mana and ability haste so he can keep his E toggle running and his Q flowing. It rewards exactly the sustained AoE he already brings.
Domination
Primary
Dark HarvestDamaging a low health champion inflicts adaptive damage and harvests a soul from the victim.
65% · 47.1%37% · 43.8%38% · 46.4%
Keystone plus three minors from Domination, two from Sorcery, then three shards — no runebook, no masteries.
Sorcery
Secondary
64% · 47.8%61% · 48.9%
Karthus Skill Order
Wall of Pain waits until level 4 here, the first point where Karthus can slow a target rather than just chip at it. Three ranks of Lay Waste by 5 and Requiem at 6 finish the pattern.
Karthus Abilities
Defile quietly funds the whole engine, its passive handing back mana on every kill so the damage aura keeps humming. Wall of Pain does more than slow, stripping magic resist off anyone who steps through and leaving them softer for the delayed blasts to finish.
Karthus Base Stats
Karthus Matchups
Karthus wants to reach his items untouched, so he does well against passive lanes that let him free-farm and scale. He struggles against early aggression, dive junglers, and mobile assassins who jump on his slow, immobile body before he ever comes online.
























































