everyone always talks crap when uou get a katarina pentakll... theres still skill involved...

yeah ya wait for your team to damage em a bit then e in and press R.

so mechanical

You have to wait for specific times to go in, you have to have good reflexes to E AFTER your Q is distributed to proc the damage. You can't just randomely press buttons or you'd get cc'd by a competant enemy team, (because you know, the slightest bit of hard cc, no matter how small it is cancels her ult). You have to have good awareness to E out IMMEDIATELY after you kill a target to the next vulnerable target, thus getting a penta with Kat is not as easy as everyone says. I personally think it's way easier with master yi because Q is your only damage skill and it's engraved in to people's brains to Q as soon as it's up.