First of all, this is my first ever guide, so feedback is welcome. Second, Karthus is an amazing champion, and so many people (in my opinion) play him incorrectly. This guide emphasizes his passive, and while starts slow, becomes an amazing force at the end of the game. The key to using this guide correctly is the proper use of your summoner spells and when to use your ultimate.

5/23/11 - Guide posted, game build 1.0.0.118b
5/28/11 - Started In-Depth sections, Early-Game
5/29/11 - Updated item build section, tweaks to several other sections
11/20/11 - Edited Masteries, Runes, Item build to reflect season 2 changes
11/21/11 - Added Mid Game and Late Game sections

Pretty basic mana using caster runes, other than the Revival quintessences. With these quints and the Good Hands mastery, you have 25% less time dead, which is cruicial late game when a death can take someone out of the fight for a minute. I use CD/level glyphs to help with the long recharge on the ultimate, as well as to easily build the tear.

Most people would use AP/level glyphs instead, but since my normal team usually has either a jungler that needs blue, or another AP carry, I prefer the CD/level to help cap my CD reduction. This is also the reason I don't pick up the Runic Affinity mastery.

The season 2 changes have thrown off all of the mastery pages. Many argue for going much deeper into the offense masteries with the new AP friendly masteries. I still go 21 in utility because I use revive, and I want it to be available as often as possible.

I choose to not use the experience mastery because now that it is much deeper in the utility tree less people use it, so you don't need to have it to reach level 6 before or at the same time as the other solo laners.

The extra gold at the beginning allows me to start with a third health potion, letting me stay in lane longer.

Teleport and Revive? Am I crazy? My regular team thought so at first. Now when we are tired of barely losing games because we are trying out new champions or crazy team comps they insist that I play this Karthus build to steamroll the enemy team.

Revive is the game changer here. If used properly you can save your ultimate and just keep popping your Q and dropping your W on people in your 7 extra seconds of death, then revive and finish whoever is low. This especially changes things late game when the teamfights are very hard fought. You will often net double kill and even quadra kills if used properly. Nothing is more satisfying than dying, then 12 seconds later being on a Rampage.
Revive can also be a great help in rushing to defend a tower (if teleport is on cooldown) or to stop an enemy charge/save a teammate who is running.
You need to keep in mind that it has a 10 minute cooldown however, and you should often wait that extra 10-20 seconds to respawn rather than use a 10 minute cooldown summoner spell.

Teleport has many uses. Early game you use it to get back into your lane after going B. Mid game it is used for ganking and covering a teammates lane. End game it can be used to get into position for a teamfight faster, or to save a tower (or make a timid player run away when they see the teleport swirling nearby.) One thing I like to do is teleport to a minion just behind an enemy champion who is split pushing and once I hit the ground I drop a wall and my defile, almost always netting me a kill 1v1 or even 1v2.

Upon dying, Karthus enters a spirit form allowing him to continue casting spells while dead for 8 seconds.


Allows you to keep fighting after death, something of inestimable value in a team fight, they can kill you, but you are still hurting them badly. Especially if they are fighting inside your defile. Note: Your Q range is much larger than your Defile (E) radius. With a good cooldown percentage you can get off at least 6 Qs after a death.





Creates a delayed blast at Karthus' cursor position. After 0.5 seconds, deals 40 / 60 / 80 / 100 / 120 (+30% of ability power) magic damage to each nearby enemy, this deals double damage if it hits only a single unit.

Cooldown 1seconds
Cost 20 / 28 / 36 / 44 / 52mana
Range 875


This is your main damage ability. Early game it is used to last hit and harass. By the time you have it to level 5 you will be 1 hitting creeps. Placement is key with this skill, as you need to hit only one target to get the double damage proc.
This skill is also a major problem for a lot of Karthi(plural or Karthus?) as they fail to accurately predict where the enemy will be going, and subsequently miss with this skill. Accurate placement with your Lay Waste is the difference between a good Karthus and a great Karthus.





Creates a 800 / 900 / 1000 / 1100 / 1200 distance wide wall through target point. Reduces enemy armor and magic resistance by 15 / 20 / 25 / 30 / 35 and reduces movement speed by up to 40 / 50 / 60 / 70 / 80%; debuff lasts 5 seconds. The wall lasts 7 seconds.

Cooldown 22seconds
Cost 100mana
Range 1000


An amazing slow, like Anivia's Wall it can cover and entire lane and reveal brush. With Rylai's Crystal Scepter it can be an even more effective slow, allowing nearly anyone to catch and kill the enemy. I often use it to scare enemies away as well, as few champions can effectively gank you when they are being massively slowed. The magic resistance debuff will also be very important when the enemy is stacking MR to counter you.
If/when you die, try to place the wall directly on the enemy, instead of nearby, as many champions and summoners have a flash skill, which effectively wastes the wall.





Toggle Off: When Karthus kills a unit, he restores 20 / 27 / 34 / 41 / 48 mana.

Toggle On: Drains 30 / 42 / 54 / 66 / 78 Mana to deal 30 / 50 / 70 / 90 / 110 (+25% of ability power) damage to nearby enemies each second.

Cooldown 0.5seconds
Range 550


This skill is why Karthus is such a monster. with 400 AP this will do 210 damge per second to ALL enemies in range. 400 AP is not hard to get, and this spell will activate Rylai's, making Karthus a moving slow field. Add Spell Vamp to the equation and he gets even more scary. He slows you, doing constant damage, while filling up his own health bar? Manifestly unfair. Oh, and that is all without using his wall or Q. Yep, 1v1 just about everyone will die to you, and spell vamp just gets stronger the more enemies that surround you.
This skill should ALWAYS be up if you are dead, even if there are no champions within range, you still get exp and gold for killing creeps with it.
The only negative to this skill is, if you overuse it early-mid game you will run out of mana very quickly, leaving you unable to get that last hit for a kill or with not enough mana to finish someone with your ultimate.




Requiem
After channeling for 3 seconds, Karthus deals 250 / 400 / 550 (+70% of ability power) magic damage to all enemy champions (regardless of distance).

Cooldown 180
/ 150 / 120seconds

Cost 200
/ 300 / 400mana

Range 10000



Recently nerfed to 60% of AP instead of 70% this skill is still an amazing ultimate. The other team must always be concious of their health, as a good Karthus will be watching, and his teammates should be reporting when the enemies are low. Nothing makes that Katarina madder than getting a cheap ultimate kill on teemo and running from his backup and then having the red beam of Death drop from the sky and put an end to her spree.
This skill will be what wins you the game. Even if you aren't at a teamfight you can contribute, often finishing off 1-2 champions, or getting them low enough for your teammates to finish them, getting you the assist. Sometimes teams will even run/back-off when they see your ultimate starting to channel, knowing that they all are about to take some serious damage, letting your team initiate the teamfight.
If you look at the damage there are few ultimates that compare. Often near the end of the game my ultimate hits for 550 + ~375. 925, factor in enemy magic resist and your spell penetration and you are hitting every single enemy for about 875 (this obviously varies) which is around half the hp of some of the weaker champions (ex=janna) and when you hit 5 people for ~900 damage, you are doing 4500 damage to the team. Can you name another ultimate that can do the same? Now can you name one that can do that from anywhere on the map to anywhere on the map?
This skill MAKES the other team build a magic resist item, if they haven't already because of your Q and E.

This is where it gets interesting. Start with a and
When you get to around 1k gold, clear the next creep wave and return to base to get a and
Use your teleport to get back out to the lane, minimizing the experience loss. From here it is pretty subjective, if you aren't getting ganked often and are having no trouble harassing against your enemies then build a . Otherwise, you should pick up wards and more potions.

A word about spell vamp. There are not nearly as many options for Spell Vamp as there are for lifesteal, and for good reason. Spell Vamp is simply amazing. If you can survive a few seconds of being attacked, you will stay alive far longer than expected, even when it is 3v2 or 4v2. The has a unique aura, but if someone else on your team has one, you can receive their Aura as well, giving you 50% spell vamp. This make Karthus a moving field of death late game, as he can simply turn defile on and wade into enemy groups, using spell vamp to keep his health up, while dropping insane nukes with his Q. Yes, building spell vamp means you do not reach the high AP ranges, but doing less damage per second and surviving beats doing a ton of damage and dying in 2 seconds.

Building a defensive item is always an option for Karthus, but with the proper team composition and playstyle, it is usually unnecessary. If you insist on getting a defensive item though, I recommend either a or (for magic resist, depending on enemy team composition) and a (this is hilarious when using in comjunction with Revive) or if you are getting focused by AD carries. is a viable option here as well.



This has a good mix of AP, mana, health, spell vamp, and CC. With a light helping of support for the team ( has a nice aura effect) this build is a good base build to work from, changing one or two items to get the makeup you like/need for the champions you are facing.



Karthus is a scary champion to go against. Almost regardless of how he is built he can do large amounts of damage, and often teams will stack magic resist to counter him. Do not be suprised if you see a few or from champions that would not normally build these items. This build drops the Spell Vamp, but gives you much more magic penetration, meaning you will do a bit more damage but not be as survivable. This is fine in this case because if the enemy team is building to stop you, then they will have a tougher time stopping your AD carry and you can just rack up the assists.




Pretty self-explanatory, gives you armor and magic resist, as well as a 2nd chance to pop up and reposition for your defile/wall/Q. Oh, and it gives you more health/mana, and gives you a chance to spell vamp yourself back to good health, since the AD carry has just burned its cooldowns on you.



The addition of the helps Karthus quite a bit, giving more movespeed to help with pinning champions with the combination of and as well as the nice health regen and magic resist. One is generally enough to counter most AP champions, but since it build so easily into two or three very good items it is well worth upgrading. Plus, Karthus always has an excess of gold by the end of a long game.



You can't do much better than for CC, and the hourglass will force the enemy to use their CC on someone else on your team(or not at all), allowing you to pop right out and continue to destroy them.

NOTE
With a recent patch and the addition of Tenacity a few new items were introduced.
is the tenacity item for casters, if you don't want to use . However, I find that I would rather use and lose the effect of my than to lose one of my damage items to get the spellblade.

Most teams want Karthus to have mid lane so he can reach 6 as soon as possible. The way I play Karthus this is not as vital, since Karthus is a mid-late game champion it is alright to take any lane.

In most cases you will start out with:
and

Take care laning, as Karthus is extremely squishy early game. Get your Q (lay waste) first, and only use it to last hit or harass your opponent. At level 2 get your E (defile) and continue harassing/last hitting. At 3 get Q again, and at 4 get W.

By this point, the relative skill of you vs your lane opponent should be apparent. Either you will have harrassed them to the point that they had to turret hug or you are doing the same. Some champions are very effective against Karthus early game. Here are a few to watch out for.

He hits you like a semi hits a baby carriage, and has a ranged skillshot that can make you have a very bad day. Avoid the skillshot at all costs, and stay moving to avoid his short delay aoe.

From 1-4 you will wreck him (unless you suck) but then he will be able to zone you nearly constantly if you cant land your Q to harass him. Watch for the towerdive with Pool to escape. The pool also makes him immune to your Qs, so be very careful of ganks.

The bouncing blade/shunpo combo makes Katarina one of the better harassers in the game, and coupled with your slow movement speed she can attack with impunity. Make good use of your wall and lay wastes to try and keep her out of position.

She has a free flash, and can flash->nuke->escape you over and over, making a good LeBlanc a tough opponent to land any Qs on. I always try and just slaughter her creeps as fast as possible so she wont be able to harass me as much since she is still squishy.

Well, she can insta-stealth, has a ~4s CD on her tumble and hits hard. All of this means that a competent Vayne player will have you on the defensive much of the time. Kill her creeps, stay as far away from her as you can, buy extra potions each time you go to base. Call for ganks from your jungler.

Man this guy is annoying. He can dash to attack or avoid a Q. He can dodge any damage ability if he times it correctly (including your ult). His ult is a large radius pop-up, and I believe he can avoid being slowed by your wall if he does his jumpy move. Play as conservatively as possible against Fizz, and have your jungler gank as often as possible.

By the end of early game (level 6-7) you should have gone back at least once and bought: and and if you have done well, also buy a

Mid game is where matches are won and lost. If your team outperforms the enemy in this phase, the rest of the game can be a walk in the park.

By this point you should be at least level 9, with a maxed out Q and or

Continue to dominate your lane, using your excellent map awareness (you have that right?) and teamwork to coordinate your ultimate to get kills/assists. At this point your jungler will be ganking constantly, so you should snag wraiths every time they are up (if you can leave the lane) and get blue if possible.

Assuming you are solomid, you should be assisting on every fight between dragon and baron that is in river or your team's jungle (if you can leave the lane). By now at least one tower should be down, and if it is your team's then expect many more ganks or multiple people constantly in lane against you. If it is an enemy's tower, then you should be on the other side of that. Take this time to fill your as much as possible.

By the end of mid game you should be level 12-15 and have these items: or (if your team is losing)

Depending on how well you and your team is doing you should be anywhere from level 12 to 15 by now. For the rest of the game you need to be either bait for a teamfight, or ganking constantly. The whole time picking up minion last hits and filling your

Save your ultimate for 3 different things:
1. Last hitting an enemy that has escaped
2. Initiating a team fight
3. A last resort after a death and all enemies are outside Q range

Any other usage of the ultimate is a waste 99% of the time. Especially since you aren't building a

Buy wards if you have free space, keep your jungle, baron, dragon, and as much of their jungle or probable ganking points warded as much as possible. Your team needs to get every single dragon, and prevent the enemy from getting baron at all costs. Some champions excel at sniping/stealing baron/dragon; Karthus is not one of those champions. Unless your entire team is nearby, do not waste your life by diving into the pack of enemy champions to try and steal. You will only die, leaving your team down a person should a teamfight happen.

There are several ways Karthus can be effective in teamfights.

First, as an initiator. Turn on defile and wade into the enemy group. Your team should follow, dropping all of their CC on the carries, and trying to keep all of the enemies inside your defile. With the spell vamp from you will survive longer than many people initially think, either keeping the heavy damage off of your team, or burning some of the enemy cooldowns. Constantly pop your Q and try to place your wall on as many champions as possible (or the most likely escape route).

Second, as cleanup. Let someone else initiate then follow behind with defile on, Q spamming, W dropping, and ult finishing anyone who escapes. With E + W and good Q placement, very few champions can escape you.

A possible, and much rarer, way is to initiate the team fight from the back lines by ulting when your team is in position to attack (or right as they are initiating). Since your ult is an extremely damaging attack, many lower HP champions will try to back away from the fight rather than fight 5v4 with half hp.

I will be updating each patch and as I tweak the build for different scenarios.

Soon I will add a breakdown on strategies for beating specific enemies.

I hope you like the guide, and please feel free to comment or ask questions, even if you just want to flame me. :) I won't feel bad, I know this build works, I am just trying to share it with everyone who wants to try something different with Karthus.