Feeling more than a bit inspired by Destiny I'm on the fence on how to expand out from the idea of a 4th dimensional being dying and how it would affect Humanity:

1. A friend/sibling/lover/whatever of the dead being decides to help humanity because now it's blood is part of Humanity and we can be a useful tool for it's revenge.

2. The corpse is attracting cosmic carrion eaters while it's decaying body shapes and changes the solar system.