hello
mana is usless mid-late game
idea to fix that: riuals (in its own room),
some to convert mana into stone and iron really inefficient like 100or 200mana per 1stone/iron
                                                                                                            (so it makes the player want to raid gnomes/dwarves)
enchant weapons and armor (increase mana cost exponentially)
give monsters temperary(like a day or two) buffs
summon elementals (when you kill the elementalist) and other magic based monsters
put spells on scrolls
put on magic limbs on monsters (who lost limbs)
ect.

thanks ;D