Just had a disappointing ending with a lone wizard battling the Balor Guardian. After using up his useful spells, the Balor had been little affected except that a summoned Earth Elemental knocked a little over 100 HP off him. Either immune to various energy types, or avoided effects with spell resistance and saving throws. Finally, the wizard cast Tensor's Transformation and went toe to toe with the Balor. Only problem was that the Balor never took any actions. Just stood there and got cut down. What would cause that?
I forget, but I seem to remember "Protection from Evil" preventing demons from physically touching you....maybe Im confusing games.
If so, then protection from evil is even better than I knew, and it already ranks as one of the best first level spells around.
Protection from Alignment should only prevent summoned creatures from attacking you and only with natural weapons. A Balor demon should be able to still attack you... especially one brandishing a huge flaming vorpal sword instead of trying to punch you. He probably just gave up on life, few things can survive a well built Wizard using transformation after all ^^