Answer:
Humans have two that shrink in the light and expand in the dark
I am not alive, though I never die, to no one I've ever told a lie, today I can be god's warrior, and serve him with no horror, but tomorrow I might be devil's knight, for I am what ends the light.
Seven brothers, five work all day, The other two, just play or pray.
What calls for help, when written in capital letters, is the same forwards, backwards and upside down?
I'm a god, a planet, and measurer of heat. Who am I?
What sphinxes employ and players enjoy.