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Karthus Build Guide by AIVION

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League of Legends Build Guide Author AIVION

Karthus - Hitting like a truck!

AIVION Last updated on August 30, 2011
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Middle Lane
Ranked #13 in
Middle Lane
Win 50%
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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.


Brute Force
Improved Rally

Offense: 21

Strength of Spirit
Veteran's Scars

Defense: 0

Expanded Mind
Blink of an Eye
Mystical Vision
Presence of the Master

Utility: 9

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Hello everyone, this is my first ever attempt at making a build here on Mobafire. As you can see, this is a guide on my Main, and very first Character I've ever played: Karthus, the DeathSinger. This guide will show you how I use Karthus, and some tips on how to be a successful Karthus player. I have played him for Years and can tell you what I say rings truth! He is a very great AP character if you give him time. He just demolishes everything, with his OPness! (Pfft :P)Edit: They reduced the Lay waste radius, Defile radius, and the Wall of pain length a few hours ago... Just letting u all know now Karthus is harder than usual (for most) I have to get used to him again...

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Karthus Stats

Here, Here's a match history of me doing that build. The two losses were my allies fed so we couldn't handle it, and the same thing goes for the other loss. But that stuff happens, lol. It just shows that this build can win games, if you play correctly ^^ and under that I had 2 more karthus wins, and 1 random gangplank loss, lulz.

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Pros / Cons

- A Very good Zone character (Able to control his surrounding effectively, a very good Karthus can easily mow down anyone who tries to get near him to dish out some damage.)
- Ult
- Passive makes him an effective Bomb (just goes in the midst of the action spamming his stuff)
- Defile is a beast AOE.
- Overall awesome, people just hate a good Karthus :P
- Very squishy, at least the way I build him
- Gets targeted A LOT.
- Usually is the main source of hate on the enemy team, so gets ganked a lot if you turn into a huge threat in your lanes

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Why use Karthus?

Well, He's a very good AP Caster, and pretty much a valuable asset to almost any team comp. He can dish out so much damage, and is probably one of the best Cleanup Chars out there, with his ult and all. His wall can also help turn the tide on any gank/teamfight with its epic effects.

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Greater Mark of Magic Penetration - I use Greater Marks of Insight for his marks. The Magic Penetration helps lots in the long run

Greater Mark of Ability Power - Also greater marks of potency Works good for flat AP, or Greater Mark of Scaling Ability Power, each depend on your taste

Greater Mark of Knowledge - Greater Mark of Knowledge also helps if you find yourself needing the extra mana

Greater Seal of Scaling Ability Power - I use Greater seals of force for my seals. The AP Per Level Just altogether adds in More bang for your IP than the flat AP ones Greater Seal of Ability Power. The flat AP are better used for jungling where the beginning AP is useful. However for a solo mid Karthus, which this build recommends you do, the beginning AP from the other seals are just not exactly worth it when 6 levels later from 1 your AP is gonna increase alot more than the flat AP Greater Seal of Ability Power you'd get then.

Greater Seal of Knowledge - also can use greater seal of knowledge for the extra mana

Greater Glyph of Scaling Ability Power - Greater Glyph of Force same concept for these as with the seals.

Greater Glyph of Knowledge - can also use greater glyph of knowledge for the extra mana

Greater Quintessence of Ability Power - However, I use Greater Quintessence of Potency because even though I said flat AP isnt worth it, I was meaning having all Flat AP runes isn't worth it, the quints I find are better anyway. However if you want to go with the AP per level Ones, Greater Quintessence of Scaling Ability Power Its Good too, Either one IMO works, and will help you hit like a truck! :P
When you have this rune page setup, you start out with 18 ap in the beginning ( or if you take Dorans you'd have 33 ap) Which is very good for beginning since u wont engage much. If you took the flat AP all the way you'd have 25, or 40 with dorans ring. That may sound nice but The extra damage in the beginning would only really help with farming and maybe getting a kill if your enemy is over zealous. But If you took it my approach, you'd have alot more ap in the long run than the flat ap all the way. However, It's primarily up to personal tastes.

Greater Quintessence of Magic Penetration - could also use greater quintessence of insight for the extra Magic Penetration, still works decently well.

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I go 21/0/9 with my masteries, because I find that using it like that helps you tremendously
in the long run to really Dish out a lot of damage. The extra dmg from brute force and the
attack speed helps with pushing a lot, which karthus is great at. also the 4 percent extra
magic dmg... so good :P Makes Q hit harder, Req hits harder... Very good :P (Rather have Havoc over Presence of the Master anyday) Reason why I dont
use 9/0/21 Is because Karthus really does NOT need the extra stuff you get from 21 in utility.
I mean sure the mobility is nice, but you can zone people out really quickly, and with rylais,
its ten times more effective. The 15 percent reduction time for summoner spells really doesn't
suite my style, but that one is actually up to you. The extra EXP, the decrease time spent
dead, and the one point for buffs is all you really need with karthus. The Cooldown, mana
regen, its all pretty decent too, but if played right Karthus doesn't really need all that
mana regen, and with tear's he will have enough mana for the entire game right there. Also the
increased cooldown is mundane as well since it only really counts towards ,
but you shouldn't rely on req, right? :P If you find you need to your summoner spells a lot,
or you like that mana regen/cooldown, then maybe the 9/0/21 is your particular choice.
But it's all up to you, This is a guide meaning you can follow certain things or you don't.
with the 21/0/9 approach, he Needs to hit hard, and zoneing and being able to dodge everything
people dish out at you is essential with this setup. However, if your finding yourself dieing
a little bit too much... then don't use this setup until you can effectively use lay waste in
both an offense and defense situation, use the utility approach instead... Its all about
hitting and not getting hit with Karthus. Then again, that concept changes in a team fight,
where you want to be in the middle of everything, muahaha :P

with the 21/0/9 setup, you only hit for roughly 36 damage more with Requiem, plus that extra spell penetration with everything else.
Your Q, late game, should be hitting for around 700, with about 28 bonus damage.
Defile gets to be about around 400 Dps during late game with this setup too, which is essential and powerful. It may not seem like much, but this extra damage is worth the investment compared to CDR(not important) and Mana regen (really not important if you can use your spells right, I usually never run out of mana during laning phase)

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  • Sapphire Gem: I usually Start out with This and Health Pot and a Mana Pot I find that using one of each is a great asset in the beginning of the game in the farming phase. You could also take two health pots if you find that you generally take a lot of damage early, or if your gonna face a really annoying champion like LeBlanc...
  • Catalyst the Protector: I generally get this next after i'm done farming and or need to b. Sometimes I get my first or I rush it's generally up to you and how you feel you should proceed. Also if your in Mid and fear you'll get ganked alot (I.E if enemy has a jungler) then feel free to grab some Sight Ward.
  • : Now I generally build up to here, and depending if your fed or not, you could have this baby around earlier than 10 minutes, or later around 20. But this helps balance your squishyness with a lot of health! And good mana/AP to boot.
  • : This Icon's next on the buying menu. This one is essential to outzoning your enemies. Your well timed can really slow them down a notch, Also adding in your in the factor... there gonna be slow as hell. Also the health bonus keeps you generally alive more.
  • : Next is this! This item is self explanatory... so much AP, so much to destroy!
  • : Now, This is where you can either Build into this, or you can get your in any order. I usually grab the Zhonya's first for that extra armor and status effect which is so good with Karthus. Again, up to you

If the Team focuses you alot, and there mostly DPS:

- this item can also be purchased if there's a lot of AP too, but either way, Its a decent item to get if the team has like one very good character that focuses you a lot, and your finding yourself dieing way too early.

- you could also get this too... But you really dont need much defensive items, and I never got this item with him for the year and a half that i've been using him... ever. I guess also applies here too, meh. Up to you...

If the team Focuses you and there mostly AP:

*The guardians angel also applies here*

- Very good if your getting targeted alot and need that extra MR. Also the shield it gives you is a great FU to people like or an enemy . (BTW being an Avid Karthus player will make you hate this item the more it's used against you... haha :D)

- a great MR Item that also Shreds your enemies MR and gives you an extra boost of AP. A good defense is a best offense they say :P

Also, since I think people will pop this question (Why not use with Karthus? You get a lot of AP And you can kill and be a force to be reckoned with !) Well... the truth is with Mejai's, its one of those item's that can be either a bad waste of time, or a real epic sauce item. Since you'll primarily die in team fights, targeted and such, It can be either a bad investment or not. Also you'll never know if you'll do horribly or really good with it. It's just overall not a trustworthy item... So therefore I never use it. However it's useable so if your feeling "lucky" go for it! Just don't feel sad when its 30 minutes in and you only have 5 stacks, Lol :P


- Sometimes I like getting this, the extra spell vamp is just beast, and it makes you even harder to kill in team fights :P It's a fun item for sure.

- This also is pretty good if you find yourself needing that extra Mana Regen, and I guess the CDR isn't too bad, even though Karthus only has 2 Skills that need CDR but those already have a decent cooldown as it is, and generally I'd rather invest in something that gives me more power/survivability than CDR, IMO.

- Void Staff is also a great Choice if you find yourself against a lot of MR, and I mean a lot! A very powerful AP Item.

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Summoner Spells


Teleport - It's the summoner spell of my choice. I love teleporting around to other lanes and such, and just jumping out and yelling SUPRISE RAPE! Also great for solo mid if you need a quick B because of low health or you want an item like your catalyst to help you with lane, etc. Overall Decent choice.

Flash - Oh yah... everyone loves dem flashes. It's probably the best summoner spell IMO. Get in, get out, flash through walls... just overall greatness...


Ghost - Ghost can be a very useful Spell with Karthus, Primarily for 3v3's where teleport is partially obsolete. Speedy Karthus!

Revive - I've heard that It's actually quite good with Karthus, However I'm not too sure of how it's used with him, since I've never used it before. I guess for if you divebomb a team and you wanted to like deal a ton of damage first before you ult, so you spend your 7 second spamming and such, and then u hit revive and Req... I guess? I dunno I leave it up to you to experiment with it if you so desire.

Clarity - good for noob Karthuses who are just picking him up, Or even pro's who use it for their pro stuff. I don't find a use for it though, but it's all up to tastes. I also use this when I try out a new build and am not sure how my mana situation is gonna look like. It's really a decent caster Spell, if you truly feel you need it, go for it. I just never did.

Cleanse - In ranked if I find myself up against a lot of Silencers or just in general CC chars, then on occasion I take this.

Ignite - I was told ignite is "a mage's best friend." So I guess i got curious and tried it out in a game, had Ignite/flash. It's really interesting in beginning fights, where you don't have req, and even so when you do. I haven't tried it when your in your passive yet, nor do I actually really know since I never really used it before, I'll test that out to confirm it here. But it's pretty useful to ignite the squishiest character. Since there's always a support or a summoner heal or just a heal around, the ignite locks that char down in DoT damage and just pure less health gain. Then that person's ****ed, the end. Ignite overall, moved from not too good of a spell to alternatives, congrats ignite.

Exhaust - you already have a slow, your W. Again, up to tastes.

Rally - just no :P

Clairvoyance best used with your support characters.

Heal - best used with characters like supports or tanks who like to juke with it.

Fortify - best used in a Pre made, and with anyone else but you.

Smite - only if your jungling, and this guide doesn't focus on that.

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His Passive. This really makes him a very great divebomb/Cleanup char. You could die and be very close to killing your opponent, then boom! your passive activates and you just take him out. Also as I said, when you divebomb in an team fight, your passive makes you stay in the fray, casting everything for free, even to get off one final Requiem! one of the best Passives in the game! Fitting for the Deathsinger

Lay waste - your Q. Its pretty much your Primary Damage dealing spell. Most people will ***** and say (OH BUT KARTHUS IS ONLY ABOUT HIS RRRR) Oh but.. Karthus has more than his R . He has Lay waste! And it's what makes him a force to reckon with in lane. farming, harrasing, Killing, You name it!

Wall of Pain - Your W. This wall slows the hell out of people, and reduces their Magic resistance and armor! It's One of the best slows in the game IMO. People caught up in this with you spamming Q on them forces them alot of have to use flash or cleanse to get away. It's deathly :P

Defile - Your E. This is also your AOE that just kills all! It's passive ability also mafkes last hitting minions a must, for it gives you mana back for every last hit you make. That helps keep you in lane longer, and being in lane longer = better farming = destruction of your enemy! Woo! The active that kills is a great pushing, and team fight skill. Also can be used when dead to ensure the best possible damage in a team fight, and the status effect of doesn't cause it to end, So you can activate it to have them confused on whether they should run or wait for their inevitable doom! muahaha.

Requiem - your Ultimate, and R. Your other source of kills is with this epic skill, and also what makes Karthus... Karthus :P (at least to the QQers) It has a wide variety of uses like using before a team fight to give some extra damage, or during one when you die while in your passive. Or to just simply clean up kills from afar!

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Farming/Playing Him effectively in game

Now that you got the items, summoner spells and what not down with Karthus, now comes the fun part!


Alright, In the beginning you should focus more on last hitting minions with lay waste than to harrass your enemy. only direct your wraith towards them if they try anything funny towards you, or if you just feel like getting some damage on them ( lets face it... you just can't resist spamming that epicness of a Q on people, its too much fun :D)
In the beginning, never use defile, ever. Just don't. why? It costs too much mana to sustain in the beginning, So it's not entirely worth it, Especially to farm. just conserve your mana. last hit minions with your auto attack/Q and just stay back. Only use it if your enemy is right up in your grill, and you just want to screw him over.


You gotta know how to aim that q! Predicting people's movements is the best possible way of achieving this. Get them to over extend, and then, W! QQQQQ their dead. (as long as you can predict them, and that my friends... comes with experience)
Also using Q to be Defensive is like KEY! Key key key! Its how the pros Troll you down. Nothing quite beats the feeling of killing someone as they chase you when you have like no health. (at least in this game :D)
How do we achieve this? Practice practice practice! Karthus is a champion that needs time in order to be really good with. Gotta get used to the flow of his skills, and when to use them or not, and MAP AWARENESS! Learn to Effectively Map Aware, I'll explain this in more detail in the next chapter. Don't rely on people to call the kill for you, because theres a chance they have no idea if you could kill them, and you and only you know your ults strengths, so you gotta analyze and know.

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Map Awareness/When to use that ult!

Okay, Requiem! A very OP (or so they say ....) Spell that can only be used either wrongly (like using it randomly ((aka when you first hit 6... so many karths do this, it PISSES me off... omg.)) or if you think you can kill them but you didn't analyze their health/ MR first)
Okay! Here it is!

Yup, you guessed it, THE MINI MAP! watching this sucker constantly and analyze the movement of every player in every lane. For example if you notice your enemy advancing hard on your allies, or allies advancing on enemy, click on that spot on the minimap. Watch the battle unfold while keeping yourself at bay from your enemy in your lane. If your enemy gets low and escapes, and you saw he had low enough health/MR for your ult to kill him, do it! Make sure you can do it without your enemy in your lane to disrupt you, ofc! Always, Always, ALWAYS be aware. Its the key to playing a good karthus (and also a good anyone really.) Also Keep in mind that the character that got away with low enough health/MR to Req is someone who doesn't have a way out {I.E Etc. Also If they have summoner Heal or even the heal of evilness! Like support char shields like janna's } If they have this, observe the battle, make sure they used it recently, or if your in skype,etc and you can ask your allies down there if the char used this skill yet, and they know for sure, then go for it. and if there wrong, ***** there faces off (hehe :P)

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Characters: Who to truely Fear.

These champions are people I've fought in Mid and a few times had some difficulty against. Always know your enemy, It's essential! (Btw these chars are only nuisances to me, If you find another char who just is a total *** to lane against, then find a way to overcome them best you can!)

- Leblanc... this chick gets on my Nerves so much! The best way to deal with this chick is just not try anything. With her constant teleporting around and silence nukes on you, she makes for a hard enemy to fight, if played effectively! Just stay back, farm, and best of all stay away from her! Just wait for people to gank her, or if she ****s up big time.

- Anivia can be pretty hectic too, considering she can stun constantly with her in combo with her to nuke pretty hard. Just dodge the initial Flash Frost when she shoots it at you, which is very easy to dodge after fighting so many Anivia's, and just outzone her.

- Kassadin, the anti mage character of the game. This guy's sole purpose is to screw over any mage on the enemy team. His combo... It's a pain in the ***! try to harass him as much as possible before he reaches level 6, when he starts to become a problem. When he reaches 6, just stay back as far as you can. Farm up, and just take his guerrilla warfare strategies like a man! Also if you can predict his teleport pattern, then when he does it, quickly W then try to just shoot him off with your Q.

- Mordekaiser, he's not much of a threat via insane damage/getting away strategies like the other 2, but his presence in mid can be a real downer. he just won't die! and his constant pushes/Shielding can be a real tough thing to handle. In this case, just farm up, and rely on leaving mid to gank/ Requiem to get your kills, unless he decides to be dumb and leaves an opening for you. But in the end it's usually a fruitless mid with a good morde in it.

- Annie's only a problem if you let her stun/nuke you to death. Keep her back, and just harass her down to nothing.

- Kennen can be a pain too, if played right. Just try to juke his best you can, and just try to slow him down enough to kill him without him getting too close to you. Defensive Q for the win against him!

- Veigar can also be another problem champion to go against because he can Stun you with and nuke you down with his and his , which dmg scales off his ap plus yours. The best way to fight a good Veigar is to Outzone him, and make sure he doesn't get a chance to stun you.

- She's Only a threat if you let her Snare you, Same goes for Just don't let them snare you. However Morgana Has a spell shield, so remember that she can use that to block Req, or not be slowed by your wall. Just get her when her shields on CD

- He can be a problem too if he Harasses you alot with his , and tower dives you with his . Just zone him out, and make sure to Req him only when his Pools on CD, or he'll pool out of it, which is annoying as hell >.<

- Twisted fate is the same concept as annie, just don't let him get too close to you to stun, and zone him out. However his Q can be somewhat annoying to dodge if built AP, so Be aware of it's pattern.

- Katarina can be a pretty tough opponent with her constantly and then her can be pretty annoying. Just try to stay back best you can, and when she shunpo's you, Wall her, and shoot her down.

- These next few are ranged AD's that can be a bit troublesome. Take Corki here for example: He can at level 6 can easily harass you with long range with his Just try to outzone him, and keep him away from you! The closer he is, the more he can hit you with!

- It's Kogs! He can be a troublesome creature with his extremely long ranged attacks, and his spammable Just try to dodge his ult, and keep putting pressure on him. Get up close and personal with him, it makes most Kogs lose their grip.

- URRRGOT! He's pretty mean with his combo, which deals extra damage with the corrosive and gets an auto lock on with acid hunter. Just dodge the first charge, and Just try to take him out via Wall and Lay waste. Keep your distance however! the closer you are to him, the easier he can hit you.

- He's only a problem if you let him harass you. Just screw him over with your wall and lay waste. He's way too squishy for you to have any problems with.

- She's just annoying when she can correctly place her in beginning farming phase. Just keep her at bay, and go in for the kill when she leaves an opening.

- I've barely fought mana Vaynes... but just wall her when she tries to towards you. She's then slowed down enough to Defile and Q her to death. Think of it like this: She tumbles, gets one shot off you, and thats it. You however, slow her, Defile up, and q q q q. She can't handle this, so she has to retreat: easy money.

- She has a really long range auto attack, and her can be pretty devastating when she shoots you with the charge up. Just keep her back, and outzone her, and dodge them !

- Just watch out for and you'll be fine.

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Final words

and that's it! I hope this guide Helped, and If You feel I need to add/Comment on anything not clear in this build, just let me know in the comments, and try not to be a **** about it, remember this is my first build. I only Accepts polite criticism... If I see any negative attitude in your comment, I will ignore. And also a thanks to everyone Who's commenting and helping me be a better karthus both in this game and in the build. Please try this build out! I would love to see comments on people who tried the build out, and let me know their score.
Thanks and enjoy Karthus everyone! :)