It's supposed to drain your HP for a damage boost, right? I don't lose any HP when I use Spectral Chains or the armors skill, am I still getting the damage boost?
Bloodmage has a spell-only damage boost for an Hpcost that doesn't appear above the character's head as a hit, its bugged if either the deduction or boost doesn't occur, the damage boost can be verified by performing a moderate sample size test between Bloodmage and a standard armor, then make a post in Armor Bugs with the data.