The plane crash mystery

He tells you "I know who those footprints belong to. It was a man once kind, who began to want power. He grew with evil intent learning more and more dark magic. He began to destroy worlds, killing all the organisms on them, using mini robots to help him. His name is the Black Bargainer, and when destroying a world, he kills a few people and in return kills everything else. The only two worlds that remain are yours, mine, and his, and as you can see he has already begun on yours. Follow the footprints. It's the least we can do." What do you do?