Board Thread:General Discussion/@comment-28048209-20160325202043/@comment-32388260-20170805205524

Everyone is going with number 3 but I think it's 2. This would explain why she's "Undying" and why she melts. She has determination in her. A little bit, and she had to sacrifice part of her to hold it. So she sacrificed a small part of her. And she gave her eye to Sans. Maybe to hold determination, you need to have less magical matter so you need to get rid of some.