Karthus vs Amumu Counter Pick

Only 134 recorded games back the 42.5% Karthus returns on patch 16.13.1, so the number is directional rather than settled, though the mechanism behind it is consistent. Both champions deal magic damage, which normally means neither builds an efficient defence against the other. Cursed Touch breaks that symmetry: Amumu marks targets with his basic attacks so that incoming magic damage carries bonus true damage, and Karthus, sitting on 21 base armor and 620 health, is exactly the frame that cannot absorb the follow-up.

The clash is decided by who commits first. Bandage Toss stuns and drags Amumu onto his target, and from there Despair drains a percentage of maximum health every second while Tantrum keeps cutting the physical damage he takes. Karthus answers from 450 units with Lay Waste, which pays extra against an isolated target, and with Wall of Pain to strip movement speed and magic resistance — the one tool that genuinely improves his position, since it slows the approach before Curse of the Sad Mummy can land.

Death Defied is why the matchup is not hopeless. Karthus keeps casting for a few seconds after dying, so a Requiem channel finished in spirit form turns a lost skirmish into damage on every enemy champion. At 2,490 health and 100.9 armor by level 18 he survives one misstep; two is usually final.