Quote from Shirayuki;32995:
Basic and a high rolled Darkness ES work pretty good too. It may surpass the damage of an Avenger, and doesn't require pot poison everytime you want to dungeon or something. Plus, its damn cheap and easy to make. Just that rolling 12+ on the Darkness is annoying...
Darkness on Heavy Armor is epic fail.
It's a variable enchant with only 28% chance at beating Avenger (NOT including the pot poison bonus), is not rank regardless (meaning you'll most likely screw up whatever you're trying to put it on at least once), and also has -3 Defense.
In short, it's weaker, harder to get on, and cuts your main reason for using Heavy Armor in the first place. I'm not sure about the prices, but I think Darkness costs more than Avenger in Ruairi.
Also, Basic only beats Victorious by 3 Damage. It's good, but I think its usefulness is a tad overrated.