1.You do not have a ring 2.You are not fighting against Morgoth 3.You have not used the skill previously in this battle
Magic-User:
Scry - Calcuate (sometimes incorrect) needed mana to fell a beast.
Fighter:
Bull Rush - At the cost of some mana you can run at a monster and beat it repeatedly, costing energy.
Halfling:
Kharma - At the cost of some mana you can attacks monsters by calculating how close to max your brains are (will fail when fighting certain types)
Gnome:
Invigorate - Adds slight buffs to, strength, speed, energy in a fight
Dwarf:
Rock Steady - Allows you to take hits that would fell a weaker character. (maybe it is the beard that helps)
Elf:
True Shot - At the cost of some mana you can take aim at the enemy, could hit a vital spot. Possible reduced damage from the enemy
Experimento:
Wand of Wonder - You wave your wand of wonder and random stuff happens.