Soul Eater
As far as my experience with this item, it will give +25% AP, +25% Counter and +25% HP to Demon units. The side effect is that it will -25% HP of non-Demon units that you have. I haven't test using Undead units yet.
I have tested it with units other than demons thus far: Undead recieve +11% AP, +11% Counter, and -20% HP.(I have level 8 undead mastery) My non-undead units recieved -33% HP and no negative to AP or Counter, not the -25% this other person claimed. The +25% across the board for Demons is correct, my Demons were boosted by 25% for AP, Counter and HP. There appears to be no other side effect or hidden upkeeps I can detect at this time other than -33% HP to non-demon/non-undead, and -20% Hp to undead and I have been testing rather extensively.
