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.
IMPORTANT: THERE IS A SIMILAR GUIDE WHICH I MADE BUT ITS POSTED BY A "GUEST", SO I DID IT AGAIN AND POSTED IT AS MINE, I WILL TRY TO GET THE ANOTHER ONE ERASED.
This is my first guide, and I decided to make a Karthus guide sine its one of the most fun champions arround. You are an awesome mid champ, and your ultimate will cause ragequits more then once. You will get lots of dps with Defile, which can be really useful in team fights.
The cons of playing this champ is that you are really squishy, but IMO, you can still be awesome and die a lot. I have won games and finished 27/17 for example, however this doesnt mean u will necesarily die. =P
1. Sumonner skils
I got flash for either escaping or chasing purposes, when chasing, activate your defile skill and if your target gets out of range just flash next to him. This skill has given me lots of kills and saved me as many times to.
Teleport is a realy useful skill, not much to explain here, helps you saving towers, you lose less time walking and gives you an advantage on laning phase.
You might choose another another skill instead of Teleport, your call, even Revive can be useful with karthus. (Revive + your ulti + low HP enemys = Win)
This pasive is great, after dying you can still cast spells for 8 seconds, I have killed lost of people in these 8 seconds, as soon you die you should activate your defile, cast ***, and star spamming LW like crazy sine your skills have no cost! You can also use your ultimate, but try not to waste it since it has a long cooldown.
Karthus also gets 20% less time death, + masteries its 30%, which is a LOT at late game, when others spend 60 sec death u spend only 42.
You are gonna use this more times than your regular attack, its awesome at early levels and really anoying. When hitting champions, try to make LW hit ONLY the champion because the double dammage hurts a lot and even more to squishy champions. (Twicht, Ashe, etc.)
My personal advise is, when hitting champions, dont cast it right under them (unless they are pretty dumb/slow), I usully cast it right next to them , or behind them, some champions like Teemo might be really hard to hit.
Wall of Pain:
*** is a life-saver and an awesome slower, and it also decreases enemys MR, so its pretty awesome. The reason why I maxed it last its because I find more useful the other skills and the fact that there isnt much difference between lvl 1 and lvl 5.
When being chased cast *** in front of your enemies and keep runing, most times you will survive. You can also use it to slow enemys or just to get some more damage in team fights.
This skill can deal LOTS of damage at lvl 5, and will also help you farm minions like crazy, with my build I reached like 250/300 dmg per second! Its also really helpful when you have died and you have those 8 seconds to still deal damage >=D. The pasive might help a lot at early game, every time you kill somethig you get some mana, not much, but it helps your mana pool to last longer.
This is the best skill ever (IMO), you can get a kill or kills wherever you are, it hits all champions and deals lots of damage (over 1000 with a full build). It requires some skills at the begining, u might cast it and not kill anybody and there are some people who know how to avoid dying. Banshes Veil is your worst enemy, also sivirs field, undying rage, Kyle ult., etc.
When plying this champ, u must keep an eye on all lanes and all the places where a fight is being helded and act really fast. Many people will get mad when u kill them from your spawn pool, which makes this even more fun :D
I start with a mana crystal to make my mana pool last longer, then when you have to recall buy at least the Tear of the Goddess to get its pasive in action. This pasive increases your mana pool by 4 whenever you cast a skill (you are a skill sapammer, so that wont be a problem) which will be really usefull later. Then you get the boots, oviuosly, and then Rod of Ages. You can get even more AP with 4 Archangels staff, but I choose RoA because of the health bonus and because u will still get lost of AP.
Then you turn your Tear of the Goddes into an Archangels Staff, which pasive turns 3% of your mana into AP and its stackable :D here you should have like 250 AP.
At this point the item order doesnt make much difference, u might want to get the Zhonya's Ring to get its pasive or the 2nd Archangel's to get a bigger mana pool and mana regen, it depends on you. At the end you should get the 3rd Archangels staff and u should have like 900 AP... oh yeah, 900 sounds powerful and it is >=D
One last comment on the item section, you should use the Zhonyas ring active in convination with Defile, its a great combo and a life-saver with only 1 min CD
This is my first guide, so I hope it helps people who would like to try Karthus and the ones who already use him to.
I would be glad to recieve opinions, advices, whatever.
As you might have noticed, English is not my mother tounge, I speak Spanish, so Im sorry about all the different types of mistakes I probably made, but what can I say, Im still learning :P
Good Luck with karthus and become Legendary!