Amnesia Wizard

The legendary grand wizard, Tim, has defended humanity from the hordes of darkness for decades! But Tim has gotten old and now suffers from amnesia and dementia.  The wizard once held an impressive array of earth shattering spells, but right now he can only remember two of his spells! He forgets those every 10 seconds or and remembers different ones - always one offensive spell and always one utility spell.  Will Tim, suffering from the memory loss and confusion, be able to keep protecting humanity from the forces of darkness? Does he even know he's protecting them anymore, or is he simply fighting off the growingly aggressive beasts just for his own survival?