>>715549790
Kris knows what is going to happen, and knows that it'd be very bad for the ending if the knight was defeated/unmasked in chapter 3.

Kris is complicit with the knight, but at the same time it seems pretty apparent that the Knight wants Toriel and not Undyne, going for Tori twice and then opening the church dark world to try to get her again. The only reason Undyne showed up was because of Kris' actions.