I myself did this build multiple times in PBE for fun since you cannot get banned on PBE expect for leaving(which is because of leave buster and not reports). This is a troll build and unless you want yourself reported or you are just playing on a random smurf account you shouldn't use this build in real games. This build is totally viable on PBE so don't be afraid to use it there or in bot or custom bot games :)

x4
I buy 1 earlier for the high AP and the 25% of your AP into bonus AP passive but i buy the other 3 after i buy Zhonya's and Deathfire Grasp


You can just get into middle of enemy team and deal damage while they can't damage you since your Defile still damages even if you are frozen.


The high burstdamage could be useful to tell your team who you want to kill and it can also be used to easily burst them down before suiciding.

If i could that is.

Death Defied probably the most broken passive in the game,allows you to deal damage even after you die which means you can play suicide Karthus and get away with it. Just run into the enemy team every teamfight and you should to fine.

Lay Waste who needs autoattacks if you got a bomb that with high AP kills every minion you see.It's so spamable with Death Defied because it will cost no mana,and with this build it also has almost no cooldown reduction.

Wall of Pain you could use this before suiciding as it will increase how much damage your skills will deal duo to the magic resist reduction this skill gives you,also prevents enemies from running away.

Defile crazy AOE damage with high AP. Not to mention automatic toggle when dead.


Requiem
OP Ulti. We are all probably glad/sad that this ulti does not deal 100% of Karthus AP or otherwise he would be totally OP. This ulti deals damage to all champions,regardless of distance or vision and it can at most AP Karthus can get deal about maximum 950 damage which is ALOT compared to other champion ultimates which deal usually around maximum 800-1000 damage to SINGLE target. I actually think this skill should have limit to who it hits(like people that we're in your vision for like 10 seconds before you started channeling) in exchange for scaling off 100% of your AP :)
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