Not Updated For Current Season
Step I :
Getting a good start with Karthus is the most important thing. Since you will usually be at mid it's very important to have enormous fire power right at the very beginning. With this build you should normally have around 15% of magic penetration to start with, and about 40 AP. Therefore you can spam the minions and harass the enemy in front of you. Normally, if you have the right timning with your Lay Waste ability, you should be able to kill the other mid by lvl 4 . Ideally your enemy should at least be very weakened by the time you reach lvl 6. If possible immediately after reaching lvl 6, go back home and finish purchasing meija's soulstealer and finish your enemy by distance. This will boost your AP by 16 and therefore give you an immediate edge on the battle.
Always remember that this build is for experimented Karthus palyers. It took me a while (about 150 games eith the Lich) in order to perfect this build.
Step II :
Here are a few notes of what not to do and what to do with Karthus :
Try as much as possible not to KS your teammates( it's obvious that you need a lot of money but your friends must not suffer from it! ).
Always keep and eye open for mid ganks. ( If you carelessly harass your enemy rest assure that he will call for help).
Don't gank top or bottom before you have a pair of boots and before you take wall of pain.
Many users take *** at the end of their builds, and use it only to escape. THIS IS NOT THE WAY OF THE LICH! *** is made to change the tide of battle in your favor and therefore create chaos in the other team's mind.
Always start with the purchase of the book and 1 health potion. I personnally enjoy having the clarity and heal spells and let me explain why :
With clarity you can harass the other player and still spam minions. What I usaually do is that I harrass until I have almost no mana. The other player thinks than I'm no threat anymore. When he approaches I use clarity, *** and Lay Waste to finish him. If he counter attacks I use my heal and still finish him off. If I die I still finish him off!
Many users of the Lich will use different spells, and I know that both spells are not vry effective at the end, but Once more I tell you that Karthus is all about a quick and effective start. The rest will come by itself.
The Items :
Meija's Soulstealer :
As you kill and assist kills you can more power, what else can be said. Also, since when you die you lose 1/3 of your stacks, it forces the careless users to more aware and prudent.
Sorcerer's shoes :
It's a "must have" for Karthus. People will try to resist your ult and therefore you will need magic penetration.
Rod of ages :
This will boost your AP and your health. It can be changed with some other defensive items such as warmog's armour ( when playing against good DPS/Tanks) or Hextech's Gunblade ( although borh our pretty expensive). A Lich with incredible AP and that is no more squishy, is tremendously effective !
Archangel's Staff :
Lots of mana will prepare the field for Zohnya's ring and 3% of all mana you have will convert in AP.
Deathfire Grasp/second Archangel Staff/Rylai's Staff:
Either one of these will be good. Rylai's pretty effective and will stack up with ***.
Zonhya's Ring :
120 AP and 25% of your AP is added on top of it. Don't forget to use zohnya's ability if you get stuck in a middle of a melee ( and god knows you will eventually be targeted!).
With this build you'll end up with between 689AP - 1050 AP. Nothing can kill with such power. Except Baron of course (note to myself : don't try to solo Baron!).
Since this i my first build, I'd gladly have constructive comments on it, and I'll edit it very soon in order to give you a more detail analysis of this Uber-Lich!
Don't hesitate to comment and Rate!