I picked up Karthus because I wanted a highly aggressive mid caster; also...I mean just look at him...c'mon. As I leave the platform I can feel him just begging me to slaughter fields of enemies, it's great.

So far I've only played two games and I'm 1:1 with him. (Should be 2:0 but our trust quit) Anyways I'm looking for some help. At level 14 I have found last-hitting with auto attack then using Q to bully the opposing mid basically shuts them down completely. This causes me to naturally push and open myself to ganks. I tried falling back to kill wraiths while the lane came back, but then the enemy mid gets free farm. Also I feel slow and like the CS is more money than wraiths. How should I handle lane control?

Also my ult. Obviously use for kills, but as the game progressed I found it harder and harder to kill anyone with it. Is there a rule of thumb? Am I falling behind farming somehow? (I am usually 3-4x the enemy mid in CS)

I'm also not so used to the lack of mobility. (I play Irelia or Amumu usually) Am I really supposed to just dominate lane and keep the opposing mid from roaming by hitting tower any time he tries? This has ended up with me 2v1 in my lane both times. Obviously that helps top and bot a lot, but is that what I'm aiming for?

Oddly enough...

Karthus is actually the most passive mid laner in the game 95% of the time; the 5% is when he's up against someone he hard counters.

Karthus' strong point is his ridiculous damage output late game. Utterly, completely ridiculous. E combined with Q has the highest sustained AOE damage in the game, but unfortunately this does leave him squishy, which is where his passive comes in. His job is to go into a fight, attempt to get the enemy locked down in an area, and DIE WITHIN THAT AREA, so he can continue doing craptons of damage while dead due to his passive. To compensate for his late game prescence, his early game really, really lacks. It's fairly easy to be killed as Karthus during laning phase because of how squishy he is, and the fact he has no mobility skills.

For laning phase, pushing the lane is absoloutely fine; but only if you do it in a way that your creeps suicide into the enemy tower, therefore equalising the lane quickly. While they're getting creeps off their tower, go take wraiths/wolves depending on how much time you have + if you have a jungler who needs those camps.

So...just stack AP/penetration and get the revive ability? That seems so opposite of how the games have gone. Maybe it's just because I'm so low level. So how do I farm fast enough to afford all that without dying if I'm not getting kills early?

Early game, one kill at regular gold is worth like... 15 minions. Not that much tbh.

Playing Karthus, you learn how to get good at last hitting at least with his Q, or once you have the mana and if it's safe, pushing the lane hard and fast with your E+Q spam, then farming jungle minions as long as a jungler doesn't need them, and your minions are pushed to the enemy turret.

400ish cs as Karthus on a game that stretches out to late game isn't too uncommon tbh.

Teleport/Revive Karthus is slightly gimmicky, but it's a gimmick that can and has been shown to work in certain situations; the only problem is that you miss out on flash, which could save your life a few times during the game, or make you miss out on some possible kills. In general, a teleport/revive karthus is probably better for a team that you know and can communicate with; otherwise go with the standard flash/ignite or something.

Yeah that sounds too gimmicky for me. I have been running flash/ignite but may try flash/revive. I have only been doing ~150-190 CS but the games are ending in less than 30min. Clearly I can work on that. Thanks!

Edit: I have been working on using his Q for single-target harass. The double-damage is just incredible early-game. Is that good use or should it only be for last hitting?

I personally don't like karthus as a mage. long cooldown ult combined with short cooldown on his main harass, just an odd combo of cooldowns. You build cooldown reduction you are only helping his ult, and not building cooldown reduction his ult is insane long cooldown.

I guess I look at it differently (perhaps wrong I'm obviously very new). His Q is amazing for last hits. If you learn to drop it below someone as they cast they can't see it or move in time. If positioned correctly it will just hit the champ and do double damage which seems huge. At early levels just 4-5 and they have to port back or even die.

I see the ult as dive-prevention as well as kill securing. I haven't played a lot granted, but the opposing team basically dove our turret once, I ult'd and killed both divers, and that was the last time they tried it. It is a huge global presence saying "if you ever drop below 500 health you're dead". To me that is just massive pressure on every enemy I just added without leaving my lane.

Generally if you can get free harass off, and have the mana to sustain it, go for it; otherwise just focus on getting last hits on minions.

CDR itemisation on Karthus isn't too important; it's not like you need the ult that often anyway. Blue buff, blue elixir + the 4% cdr from masteries gives you 34% cdr anyway, and just an elixir + masteries gives 14% if you ever wanted cdr.

No. Do not use Revive on Karthus. Only people who really know what they're doing run Revive on Karthus, and they're screwing around.

You don't need to zone the enemy laner as Karthus. It doesn't matter if they're getting CS since you will always outscale them if you manage to be in range of the enemy team with your passive for at least a few seconds and then ult the **** out of everything. Obviously if they're asking for it you can pummel them and possibly kill them, but that's up to you.

Also, since a majority of the time you'll ult after you die, you will not benefit from CDR AT ALL because Karthus has no CDR when he's dead/passivedead. You'll get limited benefit from mana since your spells cost nothing when you're psuedodead.

Really the only thing that you need to work on is getting every minion kill that rolls past their tower. Ulting for kills/assists in side lanes is also good.

So when I die, do I immediately pop ult? I have been spamming Q. Or is it situational?