Karthus vs Kai’Sa Counter Pick

Karthus holds 57.6% against Kai’Sa across 594 games on patch 16.13.1, a sample large enough to treat the edge as real. The split runs along damage types: his output is entirely magic, hers is classed as physical, and neither champion’s natural build helps against the other. She reaches 96.4 armor and 2,374 health at level 18, numbers that do nothing about Defile ticking on her while she tries to hold 525 attack range against his 450.

Three points decide it:

• Second Skin needs stacks. Her plasma marks build over repeated hits, so short exchanges favour damage that does not ramp.
• Killer Instinct dashes her at a champion, which usually means arriving inside Defile; if she arrives alone, Lay Waste pays its isolation bonus.
• Death Defied makes a trade acceptable — Requiem’s three-second channel still resolves from spirit form.

Her side of the argument is mobility and stealth: Supercharge upgrades into brief invisibility, Void Seeker marks from long range, and 335 movement speed matches his exactly, so she is never outrun. Karthus at 620 base health and 21 armor dies to anyone who reaches him, which is why the 450-unit gap matters more than the raw statistics. Kai’Sa wins the moment she lands a first mark unanswered.