Karthus vs Rammus Counter Pick

At 125 games the sample is thin, and the 41.6% Karthus records on patch 16.13.1 should be read as a trend rather than a verdict. The interaction behind it is unusually clean, though. Karthus deals magic damage; Defensive Ball Curl raises armor and magic resistance together and returns damage to attackers, while Spiked Shell converts those same resistances into bonus attack damage. A champion whose defence feeds his offence is a poor target for sustained area damage.

What decides the skirmish:

• Powerball into Soaring Slam arrives as a knock-up, and from 450 units Karthus has no way to break contact once Rammus is rolling.
• Frenzying Taunt forces the attack, and a taunted Karthus can neither reposition Defile nor place Lay Waste where it matters.
• Wall of Pain is the one tool that still works, cutting magic resistance and movement speed for anything crossing the screen, including a ball at full speed.

Base statistics are closer than the result implies: 645 health and 2,345 at level 18 for Rammus against 620 and 2,490 for Karthus, with identical 335 movement speed. The separation is defensive scaling — 111.5 armor plus an ability that doubles down on it, against 100.9 and no defensive tool at all. Death Defied still turns a death into a Requiem.