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Build Guide by seantow

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League of Legends Build Guide Author seantow

The Last Word

seantow Last updated on March 10, 2011
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Middle Lane
Ranked #25 in
Middle Lane
Win 52%
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.


Brute Force
Improved Rally

Offense: 9

Strength of Spirit
Veteran's Scars

Defense: 0

Mystical Vision
Presence of the Master

Utility: 21

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Sorry, clicked publish on accident. Please don't vote yet

Hi, readers. As with most champions, there is a lot of debate about how to play a champion and how to play against that champion. My goal in writing this review is to teach you item builds for Karthus, given various game situations, and also how to play the character that frequently causes the announcer to cry "quadra kill!", or better. All of the usual chapters will be included, so please stay tuned.

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For offense, I pick up the AP bonus and crit chance bonus (because I don't run and or ). On the next tier, I put 4 points in the obvious mastery, then put the 9th point in . The CDR and Spell Pen will be extremely useful throughout your matches as Karthus.

I don't put any points in defense masteries.

For utility masteries, there are several different directions that you can go. I'll tell you which ones you absolutely need, then which ones you can play with.

Tier 1: Perseverence: 3 (Increases total health and mana)
Tier 2: Awareness: 4 (Increases Exp gained)
Tier 3: Meditation: 3 (Increases MP5)
Tier 4:
Tier 5: Intelligence: 3 (Increases CDR)
Tier 6: Presence of the Master: 1 (Decreases CD for summoner spells)

As I have written it, there are 14 _must have_ points in utility. I'll try to go through it as best I can.

Tier 1: I already have 3 points in Perseverence, and I generally put the last one in Good Hands. I never run Teleport or Ghost, so Good Hands is the only useful choice for me here. However, if you do run either of those, then by all means put your point there. While those 2 masteries do nothing for me, Good Hands is only marginally helpful, given that Karthus's passive gives him 20% reduced time spent dead anyway.

Tier 2 : I already have 4 points in Awareness, so I don't need any points in this tier to move on to Tier 3, but as you fill in your extra points, you will most likely notice that you will have 4 or 5 points to spend between Expanded Mind (increased max mana) and Quickness (Tier 4, increased movement speed). I max out Quickness (3 pts) and take the rest in Expanded Mind. I will address this situation later, after I have discussed the Karthus's early game.

Tier 3: Here, your staple is Meditation (3 pts). You need the early game mana regen. I have read guides that suggest that you take Insight as a summoner spell, but even if you do, I still don't think that you should take it as a one of your masteries. The increased neutral monster buffs won't help too much, given that Karthus is supposed to die. Therefore, to get to Tier 4, you will need to either take the point in Gold/10s or the Tier 3 mastery Expanded Mind. Note that if you are soloing or, to a lesser extent, laning with a partner, gold will come relatively easy to you. Harassing is one of Karthus's great qualities, as is farming. We'll get to that later, though. If you are very comfortable with your ability to farm, then you have no need for this point.

By this point, your masteries should look like 1 of these 2:

Tier 1: 4 pts 4 pts
Tier 2: 5 pts 4 pts
Tier 3: 3 pts 4 pts

Tier 4: As I mentioned in Tier 2, I max out Quickness (3 pts). I think it is helpful for survivability early-game, ganking early-game, and getting into the mix late-game. The 4th point I take is Blink of an Eye (improved Flash), because I use Flash and not Ghost.

Tier 5: Max out Archaic Knowledge (3 pts, increases CDR). Because I don't use , I put the other point in Expanded Mind (increased max mana).

Tier 6: The last point goes here.

In summary, my build suggests the following:

Movement Speed > Max Mana
Flash > Ghost
Max Mana > 1 Gold/10s

The unfortunate thing about my build is that I end up wasting a point in Tier 1 in Good Hands. That's how much better Flash is than Ghost, for Karthus at least.

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Early Game (Laning)

Oh, goodness. This is where Karthus shines. Buy your lvl 1 boots and 2 or 3 healing pots and head to middle lane. Your mindset should be "I can get all of the minion kills, I won't get denied, and I can outlane my enemy." Your goal is to hit level 6 so that you can ult and pick up kills around the map. Fortunately, Karthus has some tools to get you there efficiently.

Lay Waste ("LW" or "Bomb" or Karthus's "Q"):

The Bomb has several important aspects to be aware of:

*First, it is a smartcast ability, meaning that when you press Q, he will cast LW wherever your cursor is. You can change this in the key bindings menu, of course, but I feel that it is much more efficient as a smartcast ability. Even as a beginner with Karthus, I suggest that you practice it using the smartcast.

*Second, his bombs have a 0.5s delay between when you cast them and when they explode. While this sounds like a very short time, it is actually quite long. As you gain more experience playing as Karthus, you will find that some enemy players really know how to dodge them, and others that don't. Either way is fine; if they can dodge them, then you are getting good practice, and if not, then get fed. I will explain soon how to gank early with LW.

*Third, his bombs are relatively weak for the first couple levels. At lvls 1, 2, and 3, they deal 40, 60, and 80 damage respectively. When they only hit 1 target, however, they deal double the damage. In the early game, this is probably the most important aspect. 40 and even 60 damage are pretty slim margins to miss by when you are trying to last hit minions. Therefore, you should try to take advantage of the double damage. But you might say, "Consider 3 melee minions coming. 3 x 40 dmg = 120 dmg. If you hit only 1, then it deals 1 x 80 dmg = 80 dmg. The AoE is the best part!" Not for early game. Figure out which enemy minion your minions are focusing on, then solo bomb him. It will take a lot more practice, but it is a valuable skill. Last hitting for Karthus is not just a matter of gold, but mana as well (in conjunction with Defile ).

For beginners, work with the smartcast and get used to bomb placement. Make sure that you can land a bomb wherever you want, even if it is in the middle of group of minions. Next, get a feeling for the blast radius of the bomb. This will help you get way more last hits by solo bombing minions. Once you get these 2 skills down, you shouldn't be going oom, because you won't be wasting 3 bombs on a group of ranged minions that you won't kill. Of course, it will take longer to push the lane, but that is not your goal at this point.

Once you can reliably control their minions and your mana, harassing is the next step. With your lvl 1 boots and the long range of the bombs, Karthus is an excellent harasser. With practice, you will notice how far enemies are willing to push past their minions, when they get scared and run away, how they try to dodge. Use the skills you learned against minions against enemy champions and you should be getting in some solid hits.

It is imperative that you become proficient with LW.

Defile (Karthus's "W")

In the early game, the "toggle off" part of defile is what will make it worthwhile. Whenever you kill an enemy unit, you gain mana back. In combination with your bomb skills that you've been practicing, mana should not be an issue. Even if you auto-attack and kill a unit, you get mana back, so don't feel like you have to stick to only bombs. During the early levels, your auto-attack is still a viable ganking and minion killing tool.

At this point in the game, you don't want to toggle on Defile. It's not strong enough against minions to warrant wasting so much of your mana pool. Also, while you have Defile on, killing units does not give you mana back. On the plus side, if someone comes in to melee range to get a gank, you can toggle on Defile while you auto-attack and bomb (if you think you can win), and if you think you will die, turn it on and run away. People generally don't want to chase you in the AE, and with your increased run speed from lvl 1 boots, it shouldn't be a problem getting away. Even still, Ghost or Flash will give you another out against early ganks.

If you do manage to get a kill in mid (Good job!), clean up your lane and go for a gank. Top or bottom would love to have you, especially if the enemy team is pushing. Some well placed bombs against a stationary or stunned squishy will result in at least an assist for you. Even their tanks won't have the gear to stop you yet.

If you happen to get killed while laning (which does happen, of course), remember that you are able to cast spells for another 8 seconds for free (although you must obey CD's and channel times). Through up a wall to slow their escape, keep defile on, then bomb them a couple times. If they are close to dead, ult them.

My favorite part about playing Karthus is the early game. If you get your bombs going well, you will love it, too. You will get fed, and your ult will be the bane of the game.

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Magic Resistance

Before I start talking about items, I would like to address Spell Penetration (SP). I read the article on the leagueoflegends wikia, and while the math was right, I felt that a lot was left to be desired. I explored the topic a little on my own that I'll share. For some of you, this information may be review, but for others, it may be enlightening.

Magic Resistance (MR)
When you mouse over your MR, the tooltip reports how much the magic damage you take is reduced by. For example, if you have 50 MR, it will say that will take 33% reduced magic damage. The calculation for this is:

%Reduction = MR / (100 + Abs(MR))

where Abs() means absolute value. Plugging in 50 for MR gives:

%Reduction = 50 / (100 + Abs(50)) = .33...

which, in % is 33%.

%Reduction = -25 / (100 + Abs(-25))
= -25 / (100 + 25) = -.2

which, in % is -20%

If your MR goes negative (such as through MR reduction effects), you will take increased magic damage. In the second example, you take 20% increased magic damage.

Now, I'm sure many of you are familiar with the idea of "effective health." In this context, it means "If instead of taking magic damage that is reduced by MR against my observed health, I take true damage against my effective health, what would that effective health be?" For example:

A spell deals 150 magic damage against a target with 50 MR and 800 HP.

What we observe in-game is the spell dealing 150 * (1 - .33) = 100 magic damage to the 800 HP target, which now has 700 HP. ((1 - .33) represents "damage taken," that is, damage taken = 1 - damage reduction.). However, we calculate effective health like this:

Effective Health = Observed Health / (1 - %Reduction)
= Obs HP / (1 - MR / (100 + MR))
= Obs HP / ((100 + MR - MR) / (100 + MR))
= Obs HP / (100 / (100 + MR))
= Obs HP * (100 + MR) / 100
= Obs HP * (1 + MR / 100)
= Obs HP + Obs HP * MR / 100

The second term in this result is what gives the linear relationship that people often talk about in WoW forums. As MR increases so does effective health. Using our example from above, we have:

Eff HP = 800 + 800 * 50/100
= 800 + 400
= 1200

Which is the result that I showed before. You can also see that this is consistent with what we observed in-game; the spell did 100 magic damage after MR to the 800 HP target, thus requiring 8 hits to be killed. Using effective health, the spell does 150 true damage to the 1200 Eff HP target, also requiring exactly 8 hits to be killed. So, if we think about health in terms of effective health we can make easier calculations on the fly.

Suppose a champion has 1000 HP with 0 MR. His Eff HP is 1000. If he purchases a Negatron Cloak then he gains 48 MR. Now his Eff HP is 1480 (against magic attacks). The calculation is simple:

Eff HP = 1000 + 1000 * 48/100
= 1000 + 1000 * .48
= 1000 + 480
= 1480

A tank has ~3000 HP and 100 MR (Eff HP = 6000). Should he get Warmog's Armor or Force of Nature to have the highest Eff HP against magic? Warmog's gives 1350 HP (1350 + 1350 * 100/100 = +2700 Eff HP) while Force of Nature gives 76 MR (3000*.76 HP = +~2250 HP). Get a Warmog's. Of course, these are idealized conditions (You can feed Warmog's to max it out, you don't already have Force of Nature, etc.) The point is, the calculations are not difficult.

Now that we understand this, we can move on to Spell Penetration.

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Spell Penetration

Spell Penetration (SP)

To continue our conversation about MR, we proceed into SP. Notably, SP applies to enemies based on the type of SP. They are as follows:

1) Magic Resistance Reduction
2) Magic Resistance Penetration
3) Magic Resistance %Penetration

Items like Abyssal Scepter give reduction, Sorcerer's Shoes give penetration, and Void Staff give %Penetration. Only Reduction items, however, can get you below 0 MR. A couple of examples:

100 MR target, you have abyssal scepter, sorc shoes, and a void staff.

100 - 20 = 80
80 - 20 = 60
60 * (1 - .4) = 36

30 MR target, you have '', '', ''

30 - 20 = 10
10 - 20 = 0 (SP can't go below 0)
0 * (1 - .4) = 0

For application, most of the people that you will lane against start with 30 MR, and it is likely that it will stay there for the remainder of the game. In the early game, an enemy champion may have ~600 HP and 30 MR (~780 Eff HP). If your bombs do 80, 120, and 160 (as they get closer to ~900 HP and 30 MR (~1170 Eff HP), it may take a while to chop them down, especially as they get wise to your bombing patterns. With the SP marks and Sorcerer's Shoes , you should have them down to about 1.5 MR. Those 2 items alone will reduce your enemies Eff HP by about 200 or 300, reducing the number of successful hits to kill them by about 2 or 3.

As mentioned earlier, several carries will not buy MR items (maybe they haven't been killed enough yet) and will stay at 30 MR throughout the game. If you are in a game like this, you have no need for a void staff. You may be chopping down the tanks' MR, sure, but if they have 3000 HP and 150 MR (Eff HP = 7500), cutting it to 3000 HP and 90 MR (Eff HP = 5700) isn't going to help you make a big difference when you may only be in range for a few seconds. That being said, I generally only get a void staff if the enemy carries are getting MR (Banshee's Veil , Negatron Cloak , etc.).

Your first bit of SP on Karthus should definitely be the Sorcerer's Shoes . The 20 SP is a huge deal early game. Because your marks give about 8.5 SP and your boots give 20, you are pretty close to giving most enemy champions 0 MR against you (Most champs only have about 30 for the duration of the game). With your 15% SP from masteries, that's about as close to 0 that you need.