Defile, specially the early levels of the ability, do little damage compared to their mana cost.
Level 1 of the ability for example, 30 mana for 30 damage. That's terrible.
Please consider reducing the mana cost of defile to something like
15/25/35/45/55
that makes the mana cost 50% of the base damage.
This hurts even more now that Presense of Mind got nerfed(or is currently in the PBE) for Karthus
Baron Barian10 votesYou're not suppose to use it during the early game. The reason you level it up in the early game is help refund mana. Until the teamfighting and/or splitpushing starts, where you have the items that give you the mana needed to spam your abilities, you're not suppose to let it drain your mana.
He's a late game mage, especially since defile does insane damage at that point of the game. Until then, you have to be smart with your mana and not just go "I want to push hard because I can".
Malak1 votes[{quoted}](name=Baron Barian,realm=NA,application-id=3ErqAdtq,discussion-id=7BYcF884,comment-id=0002,timestamp=2018-03-29T21:39:48.088+0000)
You're not suppose to use it during the early game. The reason you level it up in the early game is help refund mana. Until the teamfighting and/or splitpushing starts, where you have the items that give you the mana needed to spam your abilities, you're not suppose to let it drain your mana.
He's a late game mage, especially since defile does insane damage at that point of the game. Until then, you have to be smart with your mana and not just go "I want to push hard because I can".
Karthus is under 50% win rate at all elos, and is one of the least played champions. This could make it so that he can actually use more than 1 ability until mid/late game and maybe make him a bit more viable earlier.
C9 Squeeky 2 votesNo champion should have an ability just for its passive. That's boring and unsatisfying, and it's a point-blank AOE. Not a fan of toggles myself but at least 
has range on her AOE toggle.
Baron Barian3 votesNo champion should have an ability just for its passive. That's boring and unsatisfying, and it's a point-blank AOE. Not a fan of toggles myself but at least
That's why late game, it IS used for the activated part, because at that point, you have the mana and AP to have it do a shit ton of consistent damage. Late game champions are often boring because they require the patience to build themselves up. That's the point. Be weak early, get really damn strong later. His scaling is just that nuts.
C9 Squeeky 1 votesThat is assuming you can get to the late game
Automated Riven2 votesThis is actually incorrect. Watch froggen play karthus. He uses defile to help cs in the early game.
Baron Barian1 votes[{quoted}](name=Automated Riven,realm=NA,application-id=3ErqAdtq,discussion-id=7BYcF884,comment-id=00020002,timestamp=2018-03-30T05:07:24.176+0000)
This is actually incorrect. Watch froggen play karthus. He uses defile to help cs in the early game.
Most likely because he intends to push the lane, and given how much mana that would drain, it would be a smart thing to do if you intend to recall back to base anyway, which is exactly what you ant to do before recalling.
Automated Riven1 votesI am talking like quick toggles. Not continuous draining. He just toggles it on and off for the 30 damage to help cs undertower and stuff.
Shiznyte2 votesbut if you die you get your mana back... get in there and use that passive! [slayer-pantheon-thumbs]
Malak1 votesbut if you die you get your mana back... get in there and use that passive! [slayer-pantheon-thumbs]
That's cool but dying shouldn't be part of my strategy.
Shiznyte1 votesbut his passive is literally that... I agree it could use a mana cost reduction, but dying is totally part of the strategy on Karthus. And you don't have to worry about feeding, because you can just say you are using your passive! Sometimes I even flash forward to die in a better spot on Karthus to continue team fights.
C9 Squeeky 2 votesPshh, in ARAM perhaps.
Malak1 votesbut his passive is literally that... I agree it could use a mana cost reduction, but dying is totally part of the strategy on Karthus. And you don't have to worry about feeding, because you can just say you are using your passive! Sometimes I even flash forward to die in a better spot on Karthus to continue team fights.
yea I flash into the fight as well, but id rather be useful while alive and not have to purposely die
C9 Squeeky 1 votesNo strategy should involve being stationary throwing out delayed Qs or a gray screen and losing pressure on the map.
ViciousSummoner2 votesIf this is what you commonly build on 
Start playing this instead:
Poke is a relic of the past. You do nothing in team fights. You do nothing in lane. You do nothing all game except KS. If you fall behind you stay behind forever.
Super anal cleanser will make the enemy team want to FF after seeing how OP you are causing all 5 of them will jump onto the boards to make circle jerk posts about how OP is. You do everything in team fights. You dominate lane. All the kills are your kills and everyone is KSing you even if you didn't contribute to the kill. Fall behind? LUL you never fall behind all you do is scale infinitely. You'll be so powerful that the enemy team will always want to 5 v 1 you even if you're inside your own base.
My Waifu Vanilla1 votesAbyssal Mask on a age in 8.6 OMEGALUL
ViciousSummoner1 votesWith super anal cleanser Karthus you sit on top of people, and if you're sitting on people that means your spooky mask works. Also it's for mana sustain because you gain HP from using your E and then when they damage you you get mana back to extend your E. I mean you could swap it out for a GLP or Dcap doesn't really matter I just prefer the spooky mask because it makes people scared.
mew281 votesYour build sucks you have no mana other then abisal and even then your going to be oom after like 20 seconds.
ViciousSummoner1 votesAnd that is exactly why you will never be able to go ultra instinct on Karthus. You limit yourself because you do not understand how the champion can function at his upper limits let alone break his given mould.
dim2a2 votesAs karthus players, I think E cost is fine. Karthus is in a weak state right now, so could use some buffs (the Q buff on PBE is nice, but I'd rather have slow on the wall back to pre-nerf status), gives more possibilities rather than raw damage.
Karthus does not have a lot going on mechanically which is what I like, I like strategic play. And managing your E mana is part of the strategy and (small part of) skill expression.
CppL2 votesIt cost 30mp but it restore 20 mp if you kill a unit.So actually it cost only 10 mp if you played correctly.
C9 Squeeky 1 votesAs someone mentioned earlier, they should also make each tick of damage faster as well
meowwow71 votesspeaking of presence of mind are they going with the lux ult treatment with kills refunding ult cost or ap version of triumph with xp tied to it instead of gold?
Malak1 votesKarthus is in the bottom 5 played champs with an under 50% win ratio at all elos. As soon as I switched champs I got gold
Maybe Q buff helps, but not sure