Thanks for the comment!
Yes, I see why the ending might feel abrupt. I didn't want to give all the answers away (like some stories do), since I want to give some reasoning to the side stories.
Side stories will include content from up to 10 years before the story (sometime after certain Echo ending) up to after Relentless ending to give variety of perspectives on what happened and how each character deals with it.
Once again thanks for reading the story!