Dont you know, poppy was not an antagonist? I already know it. When we first time met poppy, poppy was trying to help player. If you look closely to poppy's eyes, you might see the eyes was ok. But, when we met poppy in the second time, when its nearly ending, look closely again to her eyes. You might see the poppy's eyes was becoming a little black. That means the darkness has took poppy. And poppy was not hacking the train to fall. Its was the prototype. Why? When we come to the elliot ludwig's room, we see an vhs tape. In the ending of vhs tape, we might hear an likely error sound. Its the same as when poppy talking to player. We might hear the same error sound in the end. Its might be the prototype sound. So, poppy wasn't an antagonist