I Wrote this guide because mobafire was seriously lacking a good karthus guide. I have been playing karthus for a long time, and this is my gameplay of my favorite DPS mage. Karthus is NOT a burst mage. other example of DPS mages are Swain, cass, ryze. Burst mages are some like Annie, leblanc, and veiger. My defination of a burst mage is someone who can deal heavy damage and then is pretty much out for the rest of the fight. I belive burst mages are useless. when playing a DPS mage u can be in the Team fight longer and deal continous damage. (who can also carry harder when fed as a DPS mage

Marks: there are no better
Glyphs: there are no better
Seals: could be swapped for more AP but mana regen is 10x better
Quints: there are no better

21 in offence is the best for karth. getting that Execustioner slot is too good to pass up, perfect for requiem. + more AP more damage. Utility: Mana regen and neutral buff duration because you are going to be getting blue. mastering exhaust for the magic resists debuff

Rod of ages is a must because your very squishy. NOTE: I DO NOT GO TEAR OF THE GODDESS. this is because your E gives mana back on kills so u shouldnt be running low on mana. + u have runes. If you spam lay waste blindly u will run low, DO NOT DO THIS. i will explain farming later in the guide. getting tear also delays you getting rod of ages and deathcap which are a must have very early. Zhonays if your getting focus'd and abyssal will lower everones magic resists allowing who to do tons of damage and theres not a thing they can do. Wota is an awesome items for survivability in team fights NOTE: activating zhonays while ur E is on will proc spell vamp!

standard never max anything but Q first, if invading use Q to check bushes or get wall first for AOE slow, always max E second for more mana per kills and damage requiem when u can.

Poeple who DONT want to play against are burst mages,
Leblanc is SCARY AS **** if you play her STAY back last hit at your tower. if your still having trouble BUY GIANTS BELT AND SPELL VAMP this way you can survive her burst with HP, and then spell vamp back to full health while last hitting minions.

Cass is also a problem dodge her Q's and u can out poke her
kassadin is tough but u can do it. if he ults in put a wall behind him, when he walks threw, turn E on and Q the **** outta him if he does too much damage build MR and health to survive

THE WORST THING U CAN DO IS GIVE YOUR LANE OPPONENT KILLS. if your getting raped u must at all costs not give them kills. farm as best as u can and have a lane switch if possible. have your jungle gank and pressure them to get u to farm.

Poeple who are bareble in lane is Ryze, just dont let him stun u and out range him with your Q FARM is KEY

galio: not much u can do but farm FARM FARM

anybody else, harass with Q when u get blue or else just FARM!

Flash get away from ganks and get in the middle of fights for your zhonya E combo
I TAKE EXHAUST. this is an awesome spell on karthus. use this and wall for a TON of decrease in magic resists + slow them to keep them in ur E longer and Qing them as they run. you will be surprised how well this spell is on karth.

as i said karthus is an awesome carry for your team. dat ult ^_^. anyway be careful to see who are laning against, karthus NEEDS farm to be a great threat. he lacks burst damage so he is easy to zone out. when this happens farm at your tower and prey for ganks. other wise farm and then when u feel conformable harass with Q then wall, put on E exhaust and watch there health melt as you Q away.

PROS: Cons:
a lot of damage in team fights, Very Squishy early game
great AOE slow and debuff, Needs farm to reach full potential
.9 second cooldown Q, no escape when over extended
great aoe damage, beware of CC
global ult! :o , tough laning phase
can deal tons of damage after death , is often focus'd in team fights

Karthus is easily zoned out, so if this is happening to you theres a few steps u can take.
Jungle pressure is essential. Have your jungler keep pressure on your lane. (not camp) but pressure. Meaning have him reveal himself to your opponent. notifing that hes there. he will step back and fear the jungler. if he doesnt and continues being aggresive wall behind him and have jungler gank. Make sure you ward both sides. or if u just have one stick to that side.

you are HUGE in team fights. so be careful on positioning. The old saying "Karthus us suppose to die in team fights" is NOT TRUE. you are 10x more of a threat if your alive so dont just go rambo and flash in the middle then die and ult. you wont be doing your full damage potential. You wall is huge too. there are many different uses. use it to protect ur AD carry or use it to split there team and cause lots of confusion. annotation TIP is if you see enemy team going for dragon, or baron and are about to initiate USE YOUR ULT, send them all to half HP then go in, this way it will give your Team a HUGE health advantage for a guaranteed win. NOTE: your passive gives you a free ult if you die and extra damage but again you are 10x more dangerous if you are left alive. ANOTHER TIP: if your taking to much damage zhonyas, then flash out of fight, ULT, then go back in this way u get your ult off and deal more damage, NOTE NOTE always have your E on in fights ^_^

your W is like vlads ult: causing everyone to take more damage + is a slow
Your E is like fiddlesticks ult: massive AOE damage
Your R is just a beast ult for kills across the map, and to make people mad
your Q is a long range farming tool

saved the best for last FARMING IS HUGEEEEEEEEEEEE, you need it to rape faces. use your Q to last hit minions, but your Q to the side so ur hitting one at a time, for easier last hitting. if you are getting zoned, dont panic and get yourself killed, just play safe at your tower
Mage minions will take one hit from tower and you can Q them,
Melee minions take 2 hits and u can kill them with basic attacks at your tower. NOTE( not if your minions are hitting them.