With all the roaring knight theories out there I thought I'd put in my two cents.
I feel like whoever they are has to be someone who didn't know that Asgore was the chief of police, because they took Undyne first thinking she would have the code and came back for Asgore in chapter five, presumably once they realized Undyne didn't have it.
The problem with this is that it automatically disqualifies any of the Holidays.















