OK I got an idea why shyren's grave isn't here

The knight is an amalgamate that needs to have new monster dust infused to stop it from dying (along with Dess's body or something). That's what the sacrifices are for.

Carol and her conspirators used Shyra as the last sacrifice (who was killed sometime between the Susie diner flashback and now) - this may have been why Monster Kid and Snowdrake were so scared of the bunker.


They were planning on using Gerson's dust next, but Alvin found out, and that's why he moved the hammer into the church as early as the day before in chapter 2.

So instead, they took Undyne since it also conveniently took out a code holder