Welcome to the 4 vs 0 Karthus guide. This will lead to a 100% victory if some requirements are met. It's what people call a "Glass Cannon" build but with some tweaks.

• Insane damage.
• Fun to watch enemy team rage at your ulti.
• Cheap build due to easy creep farm
• One Teemo dies on each Requiem
• Another Teemo dies on the other 2 LoL servers in a random Dominion match.
• 1 x Lay Waste = 50% of Squishies' health
• Defile = Vacuum cleaner
• Tons of damage before you die
• Tons of damage after you die

• So squishy that as much as a creep sneezes, you die.
• Tanky enemy team = you are useless.
• Easily countered by Soraka.
• Easily countered with Zhonya's Hourglass.
• Boring early game farming.

For runes i strongly recommed:

• 4 points on Archmage is a must, as this build will give you TONS of AP.
• 4 points on Swiftness is a must as well for the gamestyle you are going to follow and will explain bellow.
• 1 points on Runic Affinity . You are the AP carry, you will be taking blue unless there's another teammate that cant offer more than you casting Requiem like no tomorrow... Also, the first time you will get blue buff, you WILL have your 1st Tear of the Goddess bought. Spam skills and charge it.

Now for the good stuff!

Your final built will look like this:


These combination of items give the Maximum AP a Karthus can ever get.
AP at level 18 with tear charged: 1149.2




Explanation:

• Karthus is a very squishy champion but has a lot of potential for some serious damage output. For the game-style this guide is about a rod of the ages (as many would suggest) would not help and only drag your damage lower.
  The idea about stacking Archangel's Staff is that its passive + the mana lets you take your AP sky-high.
  
  
• You will not get the mana from the many tear of goddess components but the 3% mana = AP stacks since its not Unique Passive.
  
  
• Each Archangel's Staff you purchase gets more and more stronger.
  
  
• Now take all that AP you ve built up from 4 x Archangel's Staff and maximize it with Rabadon's Deathcap
  
  
• In case the enemy starts stacking magic resist, sell 1 x Archangel's Staff and replace it with a Void Staff.

Abilities Damage:

• Lay Waste : 930 (single target)
  
• Defile : 397 per second
  
• Requiem : 1240

Additional potions in case you reach full build and game is not won yet:

Priorities:

>> >> >>

Needless to say you max Requiem whenever possible. Give points at levels 6 - 11 - 16.

1. Max Lay Waste first.
   You will be able to get easier last hits early game and do a LOT of damage from a great distance in teamfights/ganks etc.
   
   
2. Max Defile 2nd.
   With this at mid/late game you will be farming creeps at a ridiculously high rate. It looks really funny when sweeping over a lane. Its like a Vacuum cleaner picking up creeps.
   
   
3. Max Wall of Pain last.
   Some would say, why not give this some points earler since the length and the amount of magic resist reduction increases? Simple: what use will it make, if your other skills dont do as much damage as they should in order to take full advantage of this skill. This is a great skill for escaping or catching fleeing opponents.

At first, the summoner spells i chose for this build might look weird for you but i will explain shortly why they are the best for what you are about to do in-game.

• Teleport to save any turret under attack by creeps + enemy pusher. Switch defile on and farm 2-3 minion waves and go buy a Ferrari with the gold you've earned.
  
  
• If there is an opening and the enemy team is busy at the one half of the map, use teleport to backdoor any turret available on the other half. Now, before you go comment "Bd karthus? lol rofl noob" etc. The damage done to buildings is equal to 40% of your Ability power, that means 40% of 1149 = 460 per auto attack. Your defile will not let any creeps bother the ones you've already pushed under the enemy turret, so ~4-5 seconds and bye bye enemy turret. The enemy team will not expecting a Karthus backdoor so the response to that will be slow and most likely allow you to get turret and back to safety.
  
  
• Situation: The way you will be playing Karthus will most likely leave u dead after a teamfight. In that case, you will respawn first (also with help of Good Hands ). In late-game(nexus left) if that happens and you get the chance, teleport to enemy base and finish off their Nexus.
  Note: It mind sound crazy to you, but has happened many times to me with this build.

• Escaping enemy? no problem. Defile on - pop Ghost - Wall of Pain - take Kill!
  
  
• Got ganked mid-lane? no problem. Defile on - pop Ghost - place Wall of Pain sideways - hug turret!
  
  
• Teamfight playstyle: Pentakill! will explain bellow!

This is the main reason why this build is so OP.

{ Early Game }:

• Focus on farming like your life depends on it (which it does)
• Watch lanes and chat for your teammates to call for Requiem and get some kills or assists. Careful to observe the situation and make sure your target WILL die weather it is from you or your teammates waiting for your Requiem to strike.

{{ Middle Game }}:

• Get blue buff
• Farm like crazy using Defile
• Teamfights:
  1. Place a Wall of Pain sideways in the middle of enemy team
  2. Defile On!
  3. Spam Lay Waste
  4. Requiem recalling enemies

Important Note: If your team is not doing so well and you don't think you can win a teamfight like that, consider casting Requiem the second the fight is initiated. This will give your team a MAJOR headstart and most likely Ace. Make sure you stand somewhere safe to cast it otherwise an enemy champion might interrupt it.




{{{ Late Game }}}:
Real fun starts here!

Steps to follow:

1. Get in position behind your team or hidden in a bush.
2. YOU initiate the fight by pinging or informing your team beforehand or this will end up in a disaster.
3. Ghost + Defile On!
4. Run INTO the enemy team and place Wall of Pain in them making sure you will place yourself inside the wall too.
5. Spam Lay Waste until you die. Spam 2 more times after dead
6. Hit Requiem

• You are dead.
• Your team Aced. (remember the 4 vs 0) ;)
• Minimum 2 Turrets down every time this is done.
• GG.

That's all for my Karthus kamikaze guide. I hope it works well for any of you who might try it out as it did for me.

• Any feedback is appreciated.
  
  
• If you see any errors please inform me.
  
  
• Let me know your experiences if you have tried this build by commenting bellow.
  
  
• Please vote.
  
  

Edit:

• Corrected Ability Power to include +5% from 21 offense in masteries.
• Updated Items section to include consumable potions.
• Added cool orange separator thingies.
• Added Pros/Cons