Karthus

Arena changes

• Q: AP ratio changed to 35% AP.
• W: Cooldown changed to 12 seconds.
• R: Base damage changed to 350 to 750 3.
• R: AP ratio changed to 90% AP.
• R: Cooldown changed to 120 to 80 3 seconds.²

• For an R one-shot build, roll for augments such as Killing Time, First Strike, Diamond-Tipped Spear, Wooglet's Witchcap, and Jeweled Gauntlet.³
• With Ethereal Weapon, start with Heartsteel and build tank or AP; Rylai's Crystal Scepter is recommended, and E can be left on.⁴

Upon dying, Karthus enters an untargetable spirit form for a few seconds, allowing him to cast spells at no cost but preventing him from moving.⁵ Patch unknown

• The level-up indicator can show the wrong ability for Karthus, as it does for Anivia and Aurelion Sol.⁶
• With Doomsayer, Karthus can use E before being crowd controlled and dying, then cast E, W, and Q in spirit form before using R.⁷

Earlier formats

• Karthus and Lillia could fight champions that needed vision because they did not need vision themselves.¹¹ 8x2 duos
• Hellfire Hatchet and Perplexity could deal damage through Karthus's ultimate.¹² 8x2 duos
• A high roll could let Karthus kill both enemies with an immediate ultimate.¹³ 8x2 duos
• Jeweled Gauntlet, Vulnerability, and Sword of the Divine together seemed balanced.¹⁴ 8x2 duos
• Each Karthus Q cast with Chauffeur moved him between teammates, making it hard to play.¹⁵ 8x2 duos
• Karthus's abilities went off where they were aimed while using Chauffeur.¹⁶ 8x2 duos
• Karthus's ultimate could deal much more damage to squishy champions with 170 magic penetration from Talisman Risk Management.¹⁷ 8x2 duos