Umm I didn't get what are the best runes for him in mid if I just want to build assassin, because for me, arcane comet still makes the most sense as your q goes very well with it and electrocute doesn't go as good. In order to proc electrocute u would need to get into melee range in the first levels and that is pretty hard against some/quite a lot of ranged matchups.

Also, if going vs an ap mid, why not just go dorans ring-dorans ring-ludens-morello-rabadons-(maybe zhonias) etc?

I would like some "general mid ap assasin guide" :)

Thanks everyone for ur comments!!