Have you try to test chapter 9 epic boss yourself? When I fight the one of five yurgimar (in another dimension), I got no mana to use. Then as I keep using the spell book, It was gone too, also with the whole potion use and settings at the top left. I believe it was a bug (difficulties: easy)
So my question is, how to beat Yurgimar...??
When you reach first phase in dimension, check bufflist of all 4 Yurgimars. This will say you, what disable every room. You need to choose 3 of 4 debuffs (No Evasion, No HP/MP regen, No Spellbook/Potions, No Mana).
do you by any chance know how to screenshot ?
By "Print Screen" button o_O What's the problem?