First of all you shold make Rabadon's more of a priority. The damage increase it gives is massive, if you were to get it after your RoA your dmage increase would be huge. I don't really support the idea of Mejai's either. Sure, it works with suicide Karthus, but if your not planning on feeding the enemy or ksing the hell out of everyone its hard to get up stacks if your playing against a half decent team. Your so easily blown up unless you build health its silly imo. You should also sell your Dorans after you buy your RoA imo, but sell it for sure, and pick up a Void Staff. You should also look into taking a few ranks in *** before L14, because being able to drop a larger wall is very deadly in team fights.

Like i said very good guide, just difrent play styles, and i can see yours working very well, keep it up the good work, feel free to PM me when you get it finished.

I see your selling point, and I respect that. I'll justify Mejai's when I fill this guide. Net's freaking slow here.

Heal is a baiting tool to me, and it can save your life... It's just that it isn't quite as useful as the others IMO. I'll go into this later. Clarity is also the same. Normally, when I run out of mana, I bait the enemy team into using their skills on you so you die, and then keep up your usefulness by casting for no mana cost. Still, it works if you don't feel like intentionally dying.

Will of the Ancients works. I never said I don't get it.

I have tried that, but doran's ring just keeps my mana up enough, so meh...

I'll finish the guide, then tell me what you think.

I main Karthus and though I am really away from mid karth and playing jungle karth I still enjoy mid and your guide does look good. there some areas I really dont agree with but I dont see personal preferance as a good reason to downvote a guide. so +1.

I thought I would share what i disagreed with and you can take it or leave it.

#1. Mejai's is a big no no. if your playing ranked then NEVER EVER, if normal If you have easy lane, but then again by the time you know it would help its too late. I find it to be not enough reward for the risk.

#2. Heal and CLarity are extremmly viable spells.

#3. WOTA is a must have item.

#4. I dont know why everyone takes skills in same order but honestly taking a 2nd point in defile at lvl 5 is the way to go, keeps your mana higher, and does not hurt your damage out put. Honestly for jungle i keep it alomst even between lay waste and defile, for lane i go q, e, q, w, e, r, then max q then max e then w take r when possible.

Good Build and plz give me good build in my build ;d