Ah, I see what we mean now. The dot you put on while having 5 charges is a 100 per tick for 3 secs, then you hit them again a refreshes it with a 80 damage per sec dot. Well then yeah I guess so. If you're attack speed is up, hold your attacks for a few seconds.
When you hit them... they will have Shadow Cripple charges
as ArchaonDkz you can reach a damage of 700 if you wait 2 seconds from each attack. You also have to take in count the damage you do by just attacking them 5 times. So, yeah, it's a lot of damage without even be revealed...
700 damage from ur ulti + ur attack damage + fayde's nuke = win.
Leave illusion in lane getting xp and last hits, go off with your fayde who is invis:
Hit, wait up to 3 sec but no over, hit, wait, hit, stun, hit, spin.
You could in theory pop your ult as you run up to someone but it will die fast and they could start running from it. It takes long enough to kill someone with fayde anyway, you don't want them any nearer to a tower.