Karthus

Middle

Bottom

Rest in Peace

Massive damage scaling and kill threat.

Sorcery

Empowered abilities and resource manipulation

Summon Aery

Your attacks and abilities send Aery to a target, damaging or shielding allies.
Manaflow Band

Hitting enemy champions with a spell grants maximum mana.

After reaching 250 mana, Manaflow Band restores 1% of your missing mana every 5 seconds.
Transcendence

Gain 10% CDR when you reach level 10. Excess CDR becomes AP or AD, Adaptive.
Gathering Storm

Gain increasing amounts of AD or AP, Adaptive over the course of the game.

Precision

Improved attacks and sustained damage

Coup De Grace

Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Presence of Mind

Takedowns restore 20% of your maximum mana and refund 10% of your ultimate's cooldown.

Offense

+5 AD or 9 AP
Flex

+5 AD or 9 AP
Defense

+6 Armor or 8 MR (match-up)

WhySummon Aery

Aery provides Karthus with reliable and repeatable damage output. When spamming [Q] in lane the extra bit of chip damage adds up to be an important factor in bringing the enemy to kill range.

WhyManaflow Band

Manaflow Band empowers your early game mana sustain so that you're able to continue harassing with [Q] and have enough mana for those critical [R] casts in the mid game.

WhyTranscendence

The extra bit of CDR from Transcendence allows you to opt into Magic Pen and raw AP in the mid game for more damage outout.

WhyGathering Storm

Gathering Storm on Karthus makes you an absolute late game monster able to completely take over a game with your [R].

WhyCoup De Grace

Karth can make great use of Coup De Grace, synergizing well with both is [R] for executions, and when he's in his passive form looking to finish a target.

WhyPresence of Mind

Presence of Mind's mana and [R] refund is massive for Karthus. When paired with CDR and Ultimate Hat, a few kills/assists will greatly reduce your [R] cooldown for another fight.