Mystara has Immortals instead of gods. These Immortals have great power and grant spells to clerics. Immortals do not die of old age, disease, or damage; they do not need to eat, drink, or breathe.
Immortals are unaffected by mortal magic and can cast spells far more powerful than those cast by mortals; and they live on other planes.
The main difference between gods and Immortals is that the latter were once mortal, attaining Immortal status through the sponsorship of Immortals who approved of their mortal accomplishments.
Immortals retain an empathy with mortals and are more willing to interfere in their affairs. By doing so, they work to achieve their own personal goals, gain further powers, and advance their Spheres. While Immortals are forbidden from acting directly against mortals, they can work through agents and prophesies.