Blind rage medal requirements

[Metathron]

Um, no I managed to do it as a mage on impossible, where rage income is seriously reduced, so larger numbers don't help the rage usage that much, because you need to afford it first.

That to me does confirm that this is more easy to attain the medal on harder difficulties. Had my battles lasted for another turn or two (like your have, and probably longer than that), I would have spent twice the amount of rage I have, playing as a warrior.