Right now all the Abilities have a mana cost. But they also seem to have a related attribute. Consider the following abilities:
Eviscerate [Swordsmanship, STR-based damage, 300 mana]
Burning Pillar [Pyromancy, INT-based damage, 300 mana]
A STR-based character generally has less access to STR-based abilities than an INT-based character has access to INT-based abilities. This seems unbalanced. STR-based characters should be just as good at using STR-based abilities as INT-based characters are at INT-based abilities.
1: All characters have 1000 mana, and more INT does not increase it
2: All abilities have a related attribute
3: Higher values for the related attribute lower the mana cost of using the ability
Consider the characters Nukez (INT 20, STR 10), Tankz (INT 10, STR 20), and Midz (INT 15, STR 15)
Nukez high INT would lower the mana cost of Burning Pillar, since it is an INT-based ability. So maybe Nukez will only pay 100 mana for using it. But their low STR would not help them with Eviscerate.
Tankz would be the opposite - paying only 100 mana for Eviscerate, but paying 300 mana for Burning Pillar.
Midz would get an advantage for both, paying somewhere in the middle for both (like maybe 150 mana each).