What's cool about the Christian Faith is that it answers the question of what happens when evil and God battle.
Satan is the literal embodiment of evil. He is so full of pride and distorted love for himself he has no love for anyone else and his number one desire is for us all to be twisted into his image-- to be as filled with hate and loathing for ourselves and others and misery and pain because of that as he is.
And then you have God. St. John tells us that God is love. He is love incarnate. He is so much love incarnate that He came human to save us and make us like Him. 2000 years ago, God and the Devil-- love and hate, good and evil-- faced off. They battled. And the outcome was that love won.
Good defeats evil. The Bible tells us that.
It's also important to note that it didn't appear this way at first. To the outside world, the disciples, even Satan himself, it looked like God had lost. Jesus was dead. God was dead. There was no hope, because you don't come back from being dead.
And then a miracle happened. Jesus came back. He rose from the dead, the tomb was empty, He appeared in the garden to Mary and he appeared to his disciples and he appeared on the road to Emmaus. It's true today. It may look like hate and evil has won and love and good has lost. But, eventually, the truth will come out. Love won. Love has won. Love is winning. Love will win.