As a biproduct of Lucifers jealously of god, he was cast out of heaven and took 1/3 of all angels with him. These 1/3 angels were damned willingly and unfaithfully to god. Lucifer was holy but angels too can go on their own volition, thus becoming fallen angels but unlike humans, cannot be redeemed like human kind.
3. The excuse for everything bad that happens in the world.
3. Psh, 9 / 11 was just an act of the Devil.