So one thing that always bothered me about Zeds lore is that it never explained why the shadow techniques were considered evil.
I mean what is so bad about making shadow clones?It really looked like they were just considered evil for the sake of drama.
However in the lores of Rakan and Xayah they fight against a bunch of guys who use "shadow magic" and while Zeds abilities were never described as magic,I am pretty sure that this shadow magic is actually the same thing as the techniques from the box.
Sure none of these shadow-guys used clone-techniques,but I actually doubt that the shadow clones are the core of the shadow techniques.They are most likely a more advanced technique.
So if these clones aren't the core of the shadow techniques,then what is it?
Well there is this one dude in Xayahs colour story,who enslaves his enemies souls/steals their essence in his sword to make himself stronger.
And that is likely the core of the shadow techniques.The ability to steal the essence of your fallen enemies to increase your own abilities.
Why am I so sure that this?
Because Zed got the same ability a few months ago during the assassin rework,as he now steals a part of the AD of his victims.
And that would explain why the shadow arts are considered evil,as they encourage you to kill others for your own gain.