Solve the below problem:
Q: You are Manfred the Magician, and you can cast three kinds of spells: sleep spells, immobilization spells and mind-wipe spells. You are confronted by your dreadful rival, Mazdrud the Feared, who is capable of invoking four kinds of shields: a camouflage shield that blocks all but your mind-wipe spell (against which it is useless), an invisibility shield that gives him even odds against each of your spells, a heavy duty shield that blocks immobilization shields, is no use against sleep spells, and gives him even odds against mind-wipe spells, and an all-purpose shield, which is gives him even odds against your sleep spell, but is useless against the other two. Assuming you can cast only one of your spells, and that you will lose the battle if your spell is blocked, which should you employ? Is it a fair game?