League of Legends Karthus Guide: Best Build, Runes & Combos

Karthus is a powerful AP champion in League of Legends known for his high damage output and game-changing ultimate. Whether you play him in the jungle or mid lane, his ability to farm efficiently, deal AoE damage, and impact fights globally makes him a strong pick in any meta. In this guide, we’ll break down the best build, runes, items, and combos for Karthus so you can maximize his potential and carry games with ease.

Karthus Abilities Overview In League of Legends

Karthus has a unique kit that focuses on constant area damage and global pressure. His passive, Death Defied, lets him continue casting spells for 7 seconds after dying, allowing him to deal damage even in death. His Q – Lay Waste is a spammable skill shot that deals bonus damage if it hits only one target, making it perfect for poking and clearing camps or waves. W – Wall of Pain creates a slowing wall that also reduces enemy magic resistance, making it easier to land skill shots and amplify your damage. E – Defile passively restores mana when enemies die nearby, and can be toggled on for continuous AoE damage around him, ideal for farming and close-range fights. His ultimate, R – Requiem, damages all enemy champions no matter where they are on the map, making it a strong finishing move after fights or to pick off low-health enemies globally.

How To Play Karthus In League of Legends

Best Summoner Spells For Karthus

The best summoner spells for Karthus are Flash and Smite if you’re playing him in the jungle, which is his most common and effective role. Flash gives him much-needed repositioning or escape, especially when trying to secure kills or survive invades. Smite is essential for jungle pathing and securing objectives. If you’re playing Karthus in the mid lane, go with Flash and Teleport for better map pressure and scaling. Both setups help Karthus farm efficiently and influence fights across the map.

Best Runes For Karthus

The best runes for Karthus in League of Legends are in the Domination tree with Dark Harvest as the keystone. Dark Harvest synergizes perfectly with Karthus’s poke and ultimate, letting him scale into a late-game monster. Take Cheap Shot for extra true damage on slowed enemies from your W, Eyeball Collection for bonus AP, and Ultimate Hunter to reduce the cooldown of Requiem. For secondary runes, pick Presence of Mind and Coup de Grace from the Precision tree to keep your mana flowing and finish off low-health enemies more effectively. Use Adaptive Force, Adaptive Force, and Scaling Health for your rune shards.

Best Build For Karthus

The best build for Karthus focuses on high AP and magic penetration to maximize his damage across the map. Start with Hailblade (Blue Smite) if jungle or Doran’s Ring if mid, then rush Liandry’s Torment for burn damage that scales in fights. Follow with Sorcerer’s Shoes for magic pen, then build Demonic Embrace for more burn and tank shred. Zhonya’s Hourglass is a must to survive dives or buy time during your passive. Rabadon’s Deathcap gives a huge AP boost, and Void Staff helps melt through magic resist. Optional situational items include Morellonomicon for anti-healing or Banshee’s Veil for protection.

Best Combos To Learn For Karthus

For Karthus, the best combos are all about maximizing damage with your Q spam and using your W and E smartly. In close fights, start with W (Wall of Pain) to slow and reduce magic resist, then immediately toggle on E (Defile) and begin spamming Q (Lay Waste) to deal high single-target damage—especially effective if you’re only hitting one enemy. If you know you’re about to die, position yourself deep in the fight, activate E, and keep spamming Q until you drop, then continue dealing damage in passive form. For finishing off low-health enemies across the map, always watch your minimap and hit R (Requiem) when multiple enemies are low—it’s your signature cleanup move. Use Flash-W-Q-E when trying to secure a pick or burst someone who’s out of position. Keep practicing your aim with Q, since that’s where most of your damage comes from.

Conclusion

Karthus is one of the most powerful late-game mages in League of Legends, capable of turning fights around even after death. With the right build, runes, and combo execution, you can maximize his global pressure and consistent damage. Whether you’re farming the jungle or holding mid lane, mastering his kit—especially his Q and ultimate—will let you carry games and secure kills across the map with ease.