Answer:
By Moon or by Sun, I shall be found. Yet I am undone, if there's no light around.
Useful tool for who in darkness dwell. Within you, corrupting like a deadly spell.
There is a word in the English language in which the first two letters signify a male, the first three letters signify a female, the first four signify a great man, and the whole word, a great woman. What is the word?
This is needed both for courage and hardcover books.
I make you weak at the worst of all times. I keep you safe, I keep you fine. I make your hands sweat. And your heart grow cold. I visit the weak, but seldom the bold.
The warmer I am the fresher I am.