By saying magikills cost is the same as medusas: Today I have finally reliesed, that the magikill only cost 500 gold and 400 mana!!! I have played the most time in the campagne, and there he cost 500 gold and 500 MANA. Man I was surprised when I saw he only cost 500 gold and 400 mana now...
After all this time? You still didn't realize?
And, a ninja can kill medusa/marrow with Shinobi 2 and a quick strike afterwords. But it's almost certain that the ninja will die. But for now, lets compare the prices.
Shadowrath : 450g 200 m.
Medusa : 500g 400m
Marrow : 400g 400m
There. Look how a puny ninja can pwn a unit that is higher tier than them? Also, only both of these or our only option to kill mages which are hiding behind a wall. Behind the wall, they're almost untouchable.
Order have meric. When meric is spammed, units heal quickly. But chaos? They only have a puny regen. It may be good early, but it's useless late game. How is it supposed to heal a severely injured giant? Order can have as many as meric as they want, so that the units heal MUCH faster.
Poison Spray. It's so much more effective than Venom Flux. While Venom Flux stays for 20 secs, and Poison Spray is only one use and can be used again, it's useless. Why? Because of its range. Medusa will have to go upfront to poison tank units. Not really worth it. And it's dodgeable too. And Order have Merics for insta-cure. Chaos passive cure kicks in slower. It can almost kill wingidons.