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Karthus Build Guide by Luelen

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League of Legends Build Guide Author Luelen

Karthus, Layer of Waste

Luelen Last updated on February 20, 2012
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Team 1

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Middle Lane
Ranked #25 in
Middle Lane
Win 51%
Get More Stats

Ability Sequence

Ability Key Q
Ability Key W
Ability Key E
Ability Key R

Not Updated For Current Season

The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.



Offense: 21

Honor Guard

Defense: 0

Strength of Spirit

Utility: 9

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I have made a lot of changes to this guide recently, so please disregard what is below for the time being. The reason I'm publishing slightly unfinished is because I would like to get the new item build out there sooner rather than later.

This is, what I hope to become, a definitive guide to all Karthus play styles. I currently only have up a build for a standard laning Karthus. I have developed this through constant play testing, as well as by looking at and compiling discussion in other builds. I will be putting up some screenshots of my recent games in the next week or so, and hope to have up a thoroughly tested jungle Karthus guide within the month. I'll also be keeping track of all changes to the build in this post. If you need to use this guide quick then the build information in the overview above should be sufficient.

Change Log

02/13/12 - v4.0 published
12/20/11 - v3.0 published
12/04/11 - v2.0 published
10/13/11 - v1.0 published

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Pros / Cons


  • Kill anyone, anywhere on the field, thanks to Requiem;
  • Excellent zoning ability and high steady damage output thanks to Lay Waste;
  • A powerful slow that also weakens your enemies defenses thanks to Wall of Pain;
  • Amazing farming ability thanks to Lay Waste and Defile;
  • Near infinite mana supply thanks to Defile;
  • Be useful in fights after you die allowing for more offensive plays thanks to Death Defied.


  • Your Requiem is easily countered by spell shields or invulnerability from items such as Banshee's Veil, or Zhonya's Hourglass and abilities such as Tryndamere's Undying Rage or Sivir's Spell Shield as well as resurrection effects from items like Guardian Angel or abilities like Zilean's Chronoshift;
  • Enemy champions can easily mitigate your Lay Waste damage by half by standing in their minion waves or being grouped up in a team fight. This is countered in team fights through judicious use of Defile to increase your damage output;
  • Karthus is a terrible initiator due to his speed and health pool. Be careful when entering dangerous situation;
  • You are useless without mana, so watch your mana bar carefully when Defile is toggled on;
  • Karthus is easily blown up, so do not play too aggressively. If you are ganked you do not have any reliable means to survive or escape cc, so you must play carefully making sure you know where enemies are. Use wards and team chat to fix this.

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Summoner's Wrath is taken to improve your Exhaust.

Mental Force is the only other useful tier 1 mastery for Karthus. We get a little extra ability power.

Sorcery is going to let you cast Requiem more often.

Arcane Knowledge helps you ignore a a nice bit of magic resistance. Very useful at all points of the game.

Havoc gives you more damage.

Blast gives us more ability power.

Archmage gives us tons of ability power (around 45 extra when maxed)

Executioner will help you finish off enemies easier. You know when they escape with a sliver of health? This should stop that. It is also extra handy because you are generally only using Requiem on enemies who are at low health, so this basically increases your Requiem damage by 6%!


Summoner's Insight will reduce the cool down on your Flash allowing you to use it more often.

Expanded Mind gives you a bit of mana each level.

Meditation gives you a little mana regeneration.

Runic Affinity is taken because Crest of the Ancient Golem is very helpful to sustain mana with this build, especially early game. Having this last 20% longer is amazing.

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Greater Mark of Magic Penetration

Greater Seal of Scaling Ability Power

Greater Glyph of Scaling Ability Power

Greater Quintessence of Ability Power

Ideal Runes

Greater Mark of Magic Penetration is a no-brainer on any ability power character because every point of magic resist than you ignore is another point of damage your abilities are going to do.

Greater Seal of Vitality is great because they add about 10 health per level to Karthus.

Greater Glyph of Scaling Ability Power adds more damage to Karthus. These are chosen over Greater Glyph of Ability Power because Karthus has great early damage, and these surpass the Greater Glyph of Ability Power by level 6. End game you will have about 19 more ability power and you will not notice any difference between the two as far as your early game goes.

Greater Quintessence of Ability Power adds more damage. These are taken because Greater Quintessence of Scaling Ability Power take too long to scale up.

Optional Runes

Greater Seal of Evasion provides survivability throughout the whole game because enemies cannot mitigate dodge. In total this is going to give you a 6.75% chance to dodge any incoming attacks which always applies, whereas with enough armour penetration, they can remove the armour granted by Greater Seal of Armor. These are only less 5% less effective early game than Greater Seal of Armor, and have the potential to be 100% more effective than them late game.

Greater Seal of Health will add 48 health to Karthus right off the bat, so if you ever feel that you could do with a bit more health to start out rather than waiting for Greater Seal of Vitality to scale up, these seals are for you.

Greater Seal of Scaling Ability Power can be taken if you don't care about defense and just want more damage. Not recommended unless you are sure you don't need the extra health.

Greater Seal of Armor will grant you 12 additional armor at the start bringing you to 24 armour (from 10% damage reduction at level 1 to 20%). This can come in handy if you're facing attack damage in mid. If you don't trust averages, or would prefer a slightly better early game at the cost of some late-game survivability, get these instead of Greater Seal of Evasion.

Greater Glyph of Cooldown Reduction can be taken if you want to pop off Requiem more often (about 7 seconds faster when Requiem is maxed)

Greater Glyph of Ability Power can be taken if you want more damage at level 1.

Greater Quintessence of Health will add 78 health to Karthus at level one, making him much more durable. This will be very effective at increasing your survivability until you get your Catalyst of the Protector. I take these in build 2 because you aren't rushing a Rod of Ages so the extra health is useful .

Bad Runes

Greater Glyph of Magic Penetration is usually added to get to 30 magic penetration. This is the base magic resist for most characters in the game allowing your abilities to do full damage against pretty much everyone except tanks. However, we have Arcane Knowledge which will give us enough magic penetration to ignore magic resistance without wasting three glyph slots on magic penetration runes.

Greater Seal of Replenishment is a waste of nine slots when there is a mastery that does basically the same thing. You only need mana regen for early game anyway, since Defile will give you a virtually endless mana pool. You have enough points after getting the important masteries to do this, so save 9 seal slots for better runes.

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Summoner Spells

Flash is for running away, teleporting out of a Zhonya's Hourglass -> Defile combo or to catch a fleeing enemy.

Exhaust is going to help you kill fleeing enemies, kill/survive melee characters who can charge you, ( Exhaust, Defile, Lay Waste until the start to run, Wall of Pain, then Lay Waste till dead/escaped). It can also going to help you run away when Flash or Wall of Pain are on cooldown.

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Unique Skills

Death Defied will let you keep doing damage after you are dead. Just drop your Wall of Pain, pop Defile and Lay Waste until you're truly dead. It's especially important to drop your Wall of Pain in a team fight because it will reduce the armour and magic resist of every enemy hit, as well as slowing them giving your team a nice advantage from beyond the grave. This is going to let you be more aggressive to take down an enemy if you need to.

Lay Waste is your main damage dealer. It is a pretty strong AoE that deals double damage when you hit only a single target with it. It also reveals the fog of war around its blast radius, so it is an easy way for Karthus to scout bushes.

Wall of Pain is an extremely underrated ability. It is an AoE that slows for 80% and reduces the armor and magic resist of all enemies caught in it by 35 while they are standing in the wall and then for 5 seconds after. This is a big advantage in team fights if you get the placement right and makes it very easy to escape and to chase down enemies.

Defile is how Karthus can keep his mana up while spamming Lay Waste. When kept at the same level as Lay Waste, Defile's passive is going to return the cost of the spell, plus a little extra, every time you use it to last hit. This is what makes Karthus such a great farmer, he should never have to leave a lane because he is out of mana. As far as the active goes, the only real times to use it are when dead, with Zhonya's Hourglass invincibility, or when you are chasing someone down. If you are using it while still alive you better have an Archangel's Staff or Crest of the Ancient Golem if you hope to get any prolonged use from it without running out of mana. This skill is very risky to use in any other circumstance because it puts you right in the middle of the enemy team, where you are just going to get focused down in two seconds.

Requiem is definitely Karthus' most unique skill as it hits every enemy on the map, regardless of position. With good team co-ordination you should be getting kills all over the map every few minutes. No one is safe from your Requiem so the enemy team will be need to play much more defensively because even if they escape a fight, your Requiem can still finish them off in whichever bush thy are hiding in. Just make sure you won't be interrupted while you're casting it and that it will kill them or it will be wasted. If your team has a lot of burst champions you could also choose to cast Requiem at the start of a team fight to give your team an edge by making it easier for your burst champions to one shot. The most important part of using this skill is to not use it to steal kills in other lanes, use it only to finish off escaped enemies.

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Skill Sequence

Ability Sequence
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Lay Waste is maxed first as it is your only way to harass and deal consistent damage.

Wall of Pain should be maxed second as it will help you to escape and chase down enemy champions.

Defile will be maxed last because all we really want it for is the passive.

Requiem should be upgraded whenever you can.

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Build One - Actual End-Game Ability Power: 721

Early Game

Sapphire Crystal will give you enough mana to spam Lay Waste right away, and also builds into Catalyst of the Protector.

Health Potions are what you spend the rest of your starting cash on. This will help you stay in the lane longer and will allow you to play more offensively if you need too. Grab one every time you go back to base.

Boots of Speed are taken to increase your miserable speed.

Catalyst of the Protector adds health and mana, fixing survival and mana issues, and it provides a very powerful passive that will increase your lane sustain.

Core Items

Rod of Ages will give you even more health and mana, keeps the same passive as Catalyst of the Protector and increases your damage. Pick this up as early as possible so that it can build up.

Sorcerer's Shoes' magic penetration is going to bring you up to 30, negating it for most characters other than tanks. The movement increase is nice too.

Rabadon's Deathcap is Karthus' favourite item. It will increase your damage big time thanks to the 30% increase it provides.

Void Staff will be needed to penetrate the magic resistance they will stack to counter you. As soon as your start seeing Negatron Cloaks popping up on the other team, you will want to pick this up ASAP. If they end up not stacking magic resistance, switch it out for one of the situational items below.

Luxury Items

Lich Bane is a very powerful item, and lets Karthus break turrets over his knee. Since Lay Waste has a 1 second cooldown, you can pop the Lich Bane passive as soon as its up to deal up to around 700 damage per hit! In addition, Lay Waste doesn't interrupt your auto attacks. So your Lich Bane hits will be going out whenever they're up. The movement speed is very useful, and the magic resistance doesn't hurt.

Zhonya's Hourglass gives you some defences to make using Defile easier. The armour is handy for wading into melee range to use Defile and the active can keep you from dying if you're focused because you can negate the burst if you time it right. You also get a large chunk of ability power to boot. Feel free to pick up the Chain Vest for this item anywhere along the way if you find you need a bit of armour.

Situational Items

Which item you replace for one of these varies every game. For example, if the enemy stacks no magic resistance, lose the Void Staff for a Lich Bane. If there is a lot of cc or ability power champions, Banshee's Veil could be a better choice than Zhonya's Hourglass.

Banshee's Veil should be taken if the enemy team ability power champions are giving you a hard time.

Will of the Ancients is very useful if you are dying a lot and can combo well with Zhonya's Hourglass. This will be stealing stealing you tons of health with all the damage you're doing, so if you're taking heavy damage, using Zhonya's Hourglass invincibility with Defile up can get you just enough health to escape.

Thornmail is an item I generally don't get, but it does deal magic damage back, so our magic penetration does apply which is good. If you are fighting a lot of attack damage champions, this item will put out a lot of damage while keeping you alive.

Controversial Items

Archangel's Staff is a very good item for Karthus, but I have chosen to exclude it from this guide. Yes, it is true that he can build up Tear of the Goddess very quickly by spamming Lay Waste, even while at base with infinite mana, to make full use of an Archangel's Staff given that he also has the highest base mana in the game. I have opted out of this because I also choose to get Rod of Ages to cover all my needs, and it takes 10 minutes to build to full strength. Since both items take time to build up I would have to get them first, which means I would have to wait too long to get Rabadon's Deathcap, so my damage won't progress as fast and I will end up being pretty useless. If I waited and got the Archangel's Staff after Rabadon's Deathcap, I likely wouldn't have enough time left in the game to have it build up and be worthwhile. I take the Rod of Ages because it is overall more beneficial, adding much needed health, mana, and ability power, whereas an Archangel's Staff would only offer damage and mana, leaving you squishy. If you would like to use an Archangel's Staff in your build, please check out build 2.

Mejai's Soulstealer is taken by a lot of people, because Karthus can just suicide bomb and rack up assists post-mortem which don't get reduced because he is already dead. This means that Mejai's Soulstealer can be built up on even a bad Karthus. This strategy usually feeds the **** out of you, and you take Revive, Teleport and Good Hands to reduce on your massive death timer. The problem with this is you also feed the **** out of the enemy, and if you try to use Mejai's Soulstealer while playing a proper game of LoL, you will not see the benefits.

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Creeping / Jungling

Karthus is a godly farmer, and for this reason he should almost always take mid or another solo lane or you'll have an underfarmed team mate. Until you get Defile try to use auto-attacks to last hit, but use Lay Waste if you need to.

After you have Defile using Lay Waste to last hit becomes very easy, but make sure to watch your mana, and revert to auto attack last hitting when you need to. Be careful not to push your lane too much when you're doing this because Karthus has a hard time escaping ganks past his half of the river unless he has Flash.

As soon as you have level 3 or higher Lay Waste, focus down the caster minions in the last row with 3 of these to give you a nice place to single hit champions with Lay Waste for double damage. As soon as you have level 3 Defile minion wave become a cinch. Turn on Defile and walk into the middle of the wave, then turn it off right before they all die, and then finish off the wave with a couple of Lay Wastes. This takes just a second or two and costs you no mana.

Karthus should never really jungle with this build. Grab Crest of the Ancient Golem when you can because it will help a lot with casting Defile, but you shouldn't attempt this until around level 7. Don't try to kill Dragon until Level 9.

If you ever see an enemy going for a Ancient Golem/Dragon/Baron Nashor kill, just sit tight in a bush and when the health is low, it's very easy for you to steal it with a well timed Lay Waste. Then cover the exit with Wall of Pain and laugh all the way back to your lane. This is especially enjoyable when you steal an Exalted with Baron Nashor for your team.

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Team Work

In a team fight, drop your Wall of Pain right away to give your team a nice advantage. Stay out of melee range and Lay Waste. As soon as they start to run you should have your Wall of Pain again so drop that and pick off who you can with your Lay Waste. If there is more than one enemy that is trying to escape, cast Wall of Pain on as many as possible and start charging your Requiem where you can't be interrupted for a multi kill. Try to take note of how much health they have before you start charging Requiem and make sure it will kill them so that you don't waste it.

In the laning phase of the game, if your team mates are paying attention or you are on Skype or something you can even help get kills in other lanes through Requiem. This should help your team push pretty well since the enemy knows they are not safe anywhere on the map at low health. They will be playing much more defensively at recalling sooner rather than later.

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Thank you for reading my guide. Please leave feedback and rate my guide. If you have any questions, or thoughts about the guide, I would love to hear them.