Starter Guide: AP Requiem Karthus (Mid) Mid

AP Requiem Karthus is a problem alive and arguably a bigger one dead. Death Defied, Lay Waste (Q), Defile (E) and a global Requiem (R) mean the damage does not stop when he does.

Karthus scales harder than almost anything and reaches across the map to do it. Death Defied lets him keep casting for 7 seconds after he dies, so trading a kill for him is rarely the bargain it looks like. Lay Waste (Q) doubles up when it catches a single target. Requiem (R) hits all 5 enemy champions wherever they happen to be standing.

• Starting Items: Doran's Ring and 2 Health Potions (or Tear of the Goddess).
• Core Build Rush: Sorcerer's Shoes (magic pen maximizes Lay Waste Q single-target double damage hits), Rod of Ages (gives Karthus the health pool to walk directly into enemy teams and the mana to maintain Defile E toggle), Archangel's Staff / Seraph's Embrace (converts Karthus's huge mana pool into raw AP and grants a Seraph shield to prolong his living teamfight presence before Death Defied passive triggers), and Rabadon's Deathcap (maximizes global Requiem R damage to execute low-health enemies across all lanes simultaneously).
• Situational Options: Void Staff (needed for late-game Requiem penetration), Zhonya's Hourglass (allows Karthus to stand in the center of 5 enemies with Defile burning them while completely invulnerable), Liandry's Torment, and Banshee's Veil.

• Flash and Wall of Pain (W) synergy, paired with Teleport or Exhaust.
• Max Q (Lay Waste) first for single-target CS and poke. Max E (Defile) second for AoE teamfight damage and passive mana refund on minion kills. Max W (Wall of Pain) third for MR shred.

Combos worth drilling

• Isolated Q Farming: Hit single minions with Q (Lay Waste) to deal DOUBLE damage and trigger Defile (E) passive mana refund.
• Death Defied Ult: Walk into the center of teamfights with E Defile active -> if killed, cast 2 Qs and finish with uninterrupted R (Requiem) from passive.

Mistakes to avoid

• Don't cancel R Requiem by taking CC while alive: R has a 3-second channel. Only cast R from safe distance or while dead in Death Defied passive.
• Don't leave E Defile running out of combat: Defile burns mana fast.

• Early Game (Levels 1-5): Farm with single-target Q Lay Waste procs for double damage and mana refunds from Defile passive. Keep vision in river.
• Mid Game (Levels 6-11): Keep an eye on global enemy health bars. Cast Requiem (R) whenever low-health enemies escape bot/top lane fights.
• Late Game (Levels 12+): Walk straight into the middle of 5v5 teamfights with Defile (E) active. Place Wall of Pain (W) across enemy paths. If killed, cast 2 Qs and finish with an uninterrupted Death Defied Requiem (R).