Forgive me karlismi it does exist, but your friend was somewhat incorrect. its an item that exists however it doesn't exist as a reward for any level even though it has a model for it. on a side note, theres actually a skill for every item (and art for it!) including artlogic's badge which is just called "special" and have their own exp requirments. here are some images from the game i modded:
Devil's pact: https://gyazo.com/ac5c8852a194f134b7dff382197cccad
as you see here the different skills that take the place as items: https://gyazo.com/dbc086745ffec10892cac9a92d6d1314
karlismi mabey because it doesnt exist at all? because it doesnt? he lied. not only can you not find anything about it, it doesnt even exist in the games files.
im having a similar issue but currently only my paladins get the effect... they have 3.7B attack but -3.2B health. i find it strange that what i heavily assume is the update sparked the comment section to work and bugs are popping up everywhere. i hope if you find the source of these bugs you can fix them but for now ill just keep playing
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