Greetings, everyone! This is my first mobafire guide and its about Karthus. I'm not trying to compete with similar guides by top player/guide writers, but I'm pretty sure that with this guide I can help new Karthus players learn some basic things about this wonderful champion as well as advise some more experienced players who might have missed out on some info. So, on topic, this is an "offensive play-style" guide. I've seen many people playing as him with defensive runes/masteries or items in order to balance his damage with survivability. This could be a respectable play-style, but in my opinion he was made to be played offensively, get fed easier and remain like that until late game. You'll be squishy, you'll be the main target most of the time, but you will be damn powerful! Admit it and live with it.

Pros:

• Doing good at solo lanes.
• GREAT harass.
• Decent farmer.
• One of the best trololo ulties in-game.
• Rare to see, many people don't know most of his spells.
• Great bush scout.
• Able to avoid ganks if played properly.

Cons:

• Very squishy and usually enemies' first target.
• Expensive champion.
• Item dependent.

I use the pretty basic mage masteries. 9/0/21 to get Mpen from Archaic Knowledge , Greed , Awareness & Quickness

You should go full Mpen and AP. Armor, MR & Health runes are for *******, jk. You start with ~30(29.07) AP just from the runes. You can pretty much kill a squishy champion by putting couple of Lay Waste on his way, a matter of seconds. Early game solo with full AP. Believe me, you'll have fun.

• Lesser Seal of Replenishment: If you have mana regen issues and want to skip Clarity.
• Greater Quintessence of Health: In case you want to increase your early game survivability. But it's really a waste of quint spots imho.
• Greater Glyph of Scaling Cooldown Reduction: This is actually a good alternative. Makes Lay Waste cool-down really great and it works as good as AP glyphs.
• Greater Seal of Armor: If you notice that you die at the first jungle route or you feel extremely squishy.

• Teleport: Karthus due to Defile passive & Tear of Goddess can remain in lane for a long time if played defensively. Going back to base for shopping wont cost you any XP, as long as you teleport back to your lane right after you get your new items. Also, it becomes handy when you need to go to a lane to def after a gank/team-fight.
  
• Flash: Helps a lot at the "OSHI!" situations, when you need to finish off a champion who just ran away with 100hp! (e.g Vladimir, Tryndamere, Ezreal). Also is very powerful "anti-gank" combined with Wall of Pain.

• Ghost: Some players use it instead of Flash. In theory, after flashing you can land like 1 or 2 Lay Waste, but with Ghost you can kite the enemy with Defile up and land way more mines.
  
• Ignite: By taking this, you'll be able to do better ability combos and have a better damage output, but its really not that necessary.
  
• Heal: Karthus has low hp pool and it heals you for pretty much, but as long as you don't play with spell vamp and any remarkable hp regen, heal shouldn't be part of your play-style.
  
• Clarity: Rarely used. Can only help you early game if you can't time last hits properly. Useless late game.
  
• Revive: Seen that like 1 or 2 times. Theoretically, you can enter a teamfight with Defile & Lay Waste and damage everyone a lot, after that due to your passive you will continue that for another 7 seconds and enemies will have low health. Then, Revive, Requiem & BOOM! Le penta-kill.

Death Defied (Passive): Upon dying, Karthus enters a spirit form allowing him to continue casting spells while dead for 7 seconds. A really powerful passive. You can do decent damage during these 7 seconds and without it costing you any mana at all. 7 seconds is probably more time than you will be alive in a teamfight. =)
Lay Waste: 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 is your main ability. That's how you'll farm, harass & remain in your lane. This is the aspect you will master the more you play. You must expect your enemies' next move and place your lil' bomb there.
Wall of Pain: 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%.. Max this last. At the 5th rank the slow is one of the best in game and the range is freaking insane. Good combo with Flash as I mentioned before. The magic resistance it reduces is also pretty cool.
Defile: 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. Becomes useful early game by last hitting minions and staying more in your lane. Late game, with some respectable AP, it does insane damage and clears minion waves like a boss. Always use it during Death Defied.
Requiem: After channeling for 3 seconds, Karthus deals 250 / 400 / 550 (+60% of ability power) magic damage to all enemy champions (regardless of distance). Art of Trolling. The main source of hate. This is what makes Karthus "N00B OP LUL FOTM". If you get fed, you can't imagine the damage you can deal with it. Usually at ranked matches, forces enemies to get Banshee's Veil or Zhonya's Hourglass and using up money/item slots.

-- Starting with a Meki Pendant & 2 Health Potion. (People tend to get Sapphire Crystal instead, but with some simple calculations obviously Meki gives you more mana unless you b at the first 2 minutes ).

-- If played properly, some minutes later you will have drawn first blood, taken some assists or got plenty of cs and you'll have around 1000 gold. Go back to your spawn and get Boots to get some minor mobility and Tear of the Goddess to start stacking your mana. Teleport back to your lane and keep rolling. After that, get Sorcerer's Shoes next time you're at your base.

-- Now it's time for your big item. At most of the matches you will be pretty much fed. It's the perfect time for Rabadon's Deathcap and your ulti is already powerful. Your tear would be around half stacked and you aim for Archangel's Staff. At this point you should be able to farm for some time as long as you don't have mana problems anymore and with this AP you'll be able to 1v1 most of the champions.

-- Our new aim is Zhonya's Hourglass. A core item for us because of its active. It is expensive but it's really worth it. You can enter a teamfight with Defile up and enable its active by the time they switch to you. You'll become invulnerable but you will still AoE and do massive damage. So, hypothetically, if they target you 2 seconds after you enter the fight and kill you in another 2, you have 13 seconds of defile uptime, which believe me, is very critical.

-- Next, you get Rylai's Crystal Scepter, which gives some extra survivability, which you need late-game. Also, do not forget that the sexy slow applies to your LW too.

-- Finally, grab Void Staff. Rarely will you reach to this step because you need to be ultra-fed or reach 60+ minutes of game. Some extra Magic penetration to counter your enemies with their full builds.



You can go for this build at normal games when you get REALLY fed. When you see that at 20 minutes or less you have 10-20 kills, go for it. Sell your boots and your early game items and get these babies. With Potion of Brilliance you get around 1300AP and your ulti hits for ~1200 damage. You can easily stand at your spawn and kill stuff! But again, not a serious build and obviously not recommended for serious games.



(vs heavy CC teams) Banshee's Veil is very helpful vs 2+ enemies with CC and recommended in a ranked game. Some Crowd Control abilities can be extremely deadly for Karthus (e.g Fling, Nether Grasp, Infinite Duress or Rocket Grab)
(more survivability) You can buy it when enemy team hasn't that much CC, but you feel really squishy. You never know. This extra HP can save you sometimes!
(vs bad players) If you are getting fed early game or if you counter most of your enemies, don't just let it go. Get that really cheap item and abuse it. 200+ AP fully stacked with Rabadon's with that price? \o/

-- First of all, your ulti channels for 3 seconds before it damages all the enemies. That means that any stun/fear/knockback/silence will stop it. Also if you die during the cast, you wont continue casting with death defile. So in a teamfight don't attempt to ulti because 90% of the times you will get cc'd or die while casting. It's better to wait for the fight to end and then cast it or if it is just a harassment battle go a bit back and you'll be able to free-cast. Some times it's better to wait until you die to start casting during passive so you dont have to worry about mana or interrupts.

-- But unfortunately this is not the only problem. There are couple of spells and items that block Requiem. Banshee's Veil can block it every 45 seconds. #1 anti-karthus item. Also its less likely to see Zhonya's Hourglass, which active blocks any incoming spell/attack every 90 seconds.

-- Here are some of the spells I mentioned before: Rebirth, Intervention, Sanguine Pool, Shroud of Darkness, Spell Shield, Undying Rage & Chronoshift .

Karthus can also jungle. It's unusual but it's viable. He is very powerful mid and jungling shouldn't be your first choice except when your team really lacks a jungler or you're bored to death and want to do something different. The runes/masteries are the same except for Smite.



-- You select Smite & Clarity or Flash, you buy the classic jungle Cloth Armor and 5 Health Potion and you start moving to the wolves to avoid early jungle ganks & start clearing as soon as possible.

-- Pop 1 potion and move to blue. Start spamming Lay Waste only at the golem in order to do double damage. If you go oom, don't be afraid to pop Clarity. Your hp will drop really low when golem is about to die, but it's ok, you're not supposed to jungle as a "mage". Don't be afraid, finish him off with smite. After that, end up the lizards, pot up until you get ~50% hp and start moving to the wraiths. With blue buff you transform into super-karthus.

-- Kill wraiths, pop another potion if needed and go for the golems. Toggle on Defile and damage both of them with LW. When done pop your 4th potion and start attacking only the red lizard. Pop your last potion if you drop too low and kill it with smite, which should be up. Go "b" and get Amplifying Tome and 1-2 hp potions.

-- Your jungle started re-spawning. Repeat the route until you get level 6. Now you aim for Mejai's Soulstealer. If you followed that exactly you have your ulti and your soulstealer and you're ready to start ganking. All you have to do is ping the gank target, Wall of Pain him and start nuking him. If they have no Flash or something similar, they should die pretty quickly.

-- Generally, your role will be to make some easy ganks and check for low hp enemies around the map, ulti them and stack your lovely soulstealer.

• When you are looking for an enemy or ganking, let the tank/carry to lead the way, stay in Lay Waste range and let the others take the damage, thats not your job for sure. (tl;dr: keep your roles)
• Many people only use Defile and Lay Waste during passive and forget using Wall of Pain. You can prevent enemies from leaving the fight or killing your teammates.
• If you are confident with your normal last hits you can gain a good amount of mana. Otherwise, last hit with LW and gain almost its mana cost.
• Make sure your team knows when you hit 6 and notifies you when an enemy is low.
• REMEMBER: Don't initiate any fights. You're not the kind of the lethal ap carry that can initiate a teamfight and make enemies start running away. Don't copy fiddlesticks' ulti-flash playstyle. If you start a fight, you'll die before you even realize. Try to stay alive as much as possible and killst... finish off the enemies with Requiem.
• Ask your jungle for the blue buff. It's soooo useful for Karthus. You can spam Lay Waste like there's no tomorrow and you are able to keep Defile up for much more in a teamfight.
• If 1 or 2 low health enemies are following you to kill you and you are absolutely sure you will die stop running away and suicide! Die next to them, slow them, toggle defile and start spamming lay waste and kill these bad boys. WIN-WIN.

I hope you liked my guide and I'll be happy if you do great with this build. Karthus is not an easy champion. If you are overall new to the GAME, you better check out some cheap champions with easier skills and more balanced stats. And don't forget, practice makes perfect! :)