Everything God created was good (see Genesis 1), including the entity now known as Satan ("The Accuser"). Satan (at first, "Lucifer") was good. God is generous, and chose not to be the only Will in the Universe, so He gave angels and men intelligence and free will, which is also good.
Lucifer chose against God: that explains why Satan is such a twisted wreck: he refused goodness. I think he realizes he has lost, but he doesn't care. He wants only to destroy.