Not Updated For Current Season
Karthus, The Deathsinger
Check my other builds ->Rammus, Cho'Gath
-Amazing spell damage output
-His third skill can make he stay in lanes forever
-An awsome ult that fry anyone who dare to try to flee
-Very easy to kill if left alone
-One of the most expensive champions
Greater Mark of Insight
Magic Penetration is a nice addition and most of the others marks arent realy good for mana or ap, so magic pen is the best choice for me.
Greater Seal of Knowledge
Mana for you is aways welcome and other seals arent realy worth taking.
Greater Glyph of Celerity
Well here many people would say that AP would be a better choice but i disagree because getting 1 (3 if is glyph of force) AP per glyph of potency is not worth since your itens make you have about 700 AP so 9 (27 if glyph of force) AP is nothing compared to it, so getting about 8% cd reduction can make quite a difence.
Greater Quintessence of Intelect
I belive that 112 mana at early levels makes it a good pick, but also cd reduction runes can be taken.
Upon dying, Karthus enters a spirit form allowing him to continue casting spells while dead for 8 seconds.
Realy good passive that enable you to help in team fights even after death.
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 deals double damage if it hits only a single unit. A nice skill, with low cost of mana and cd.
Just need some time to get used to it.
Cooldown 1 seconds Cost 20 / 28 / 36 / 44 / 52 mana Range 875
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%; debuff lasts 5 seconds. The wall lasts 7 seconds. Good way to slow someone for a pursuit or a flee. Somewhat tricky to make a good place but you get used to it.
Cooldown 22 seconds Cost 100 mana Range 1000
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.
Awsome skill - You can restore your mana by kiling minions and when the gank comes you activate it and deal a LOT of damage, im serius think that early game people have low magic res and health and use this in a good area to deal damage each second.
Cooldown 0.5 seconds Range 550
After channeling for 3 seconds, Karthus deals 250 / 400 / 550 (+70% of ability power) magic damage to all enemy champions (regardless of distance).
Ah simply THE skill, when death start to whisper something and a red light apears in the head of your enemy he can do nothing but to enjoy some fireworks, followed by an ace.
Cooldown 180 /150 / 120 seconds Cost 200 / 300 / 400 mana Range 10000
Good mana boost to early levels.
movement and magic penetration.
Great iten if you dont die (if you do dont even touch), it gets up to 180 AP (at 20 stacks works great with zhonia ) and 15% cd reduction(you can try to finish it before the boots it self).
Just perfect for you, gives the mana you need to use defile for a longer duration and you get more max mana easily with your lay waste low cd.
Increases your ap and gives a boost to your atack.
A huge boost to your ap when you get this and also you can activate it in toght situations.
A good, cheap addition to your ap and also some magic pen for you.
More ap, more magic pen and some magic resist.
Early Game :
Grab the saphire crystal and go mid, and basicaly you stay using lay waste your oponent until it hp drops to about 3/5. Then you can charge using wall of pain behind him,laying waste whever possible and using exaust and ignite if needed.
Mid Game :
Now you batter walk togheter with your team otherwise you WILL die, so help them using wall of pain to slow and reduce magic res and go nuking them and if someone dares to run you simply ult (BEWARE ! if someone kills ult while youre chaneling ult you waste it !). If you die in teamfights you can still ult and lay waste them so take the 8 secs to your advantage. Use defile to kill creeps.
Late Game :
Your lay waste should do quite some damage now and defile can be used to farm most of creep waves. stick togheter with your team and keep using wall, turning defile on, lay waste and requiem if someone run (BEWARE ! if someone kills ult while youre chaneling ult you waste it !).
Thats basicaly how i play with Karthus, a hero who can nuke wuite a lot , but easily killed.