The plane crash mystery

As you follow the footprints you take pictures of them and you surf the web. You sniff them and poke them and pry them, while reading ancient books that the villager packed for you. They have useful information. Apparently the footprints belong to a man named the Black Bargainer, who has been roaming the multiverse and destroying worlds. The only worlds that remain are this one, yours, and his. He always begins by killing a few people, and in return destroying their world. He has already begun on your world. That's where this whole mess started. (What do you do)