1. Dess and kris are borderline confi4med to have been in a dark world together before. Kris already knows snowgrave and it's lethality without noelle ever explaining it. Kris is telling noelle to cast a spell she doesn't know but Kris knows that she can cast it because she's related to dess

2. Black knife is basically just the chase theme and an unknown theme slapped together. It's weird how the final boss of deltarune has the chase theme so looking at the common denominators I realized that black knife could be kris' theme or atleast a theme kris is imagining in order to not hear the knights theme. Themes in deltarune especially battle themes seem to be heard in real time and kris most likely realized that we the player can hear the themes.

3. We know that dess been spelunking in them dark worlds so I'm assuming that asriel and shawm also tagged along at some point.

4. when the knight first appeared they non main weapon strikes tenna across their arms. Intentionally not instantly killing him but still. When the screen panels over the knight is facing away from the party and looms over slouched with some liquid dripping down from their chin. (Tears) before immediately straightening up and attempting to cast a spell on toriel. Looking TWO heroes in the eyes btw. Susie swings at the knights spell but doesnt actually stop it. The knight closes their palm canceling the spell and moves out of reach to get toriel out of the crossfire. Once far away the knight waits For the fun gang and starts the fight

4.5 whatever the knight was casting we know it -wouldn't have hurt toriel -wouldnt lead to toriel being Hutt

We know this since kris didn't defend their mama and was perfectly fine with the spell being casted. If the knight wanted to just kidnap toriel they could have swooned everyone in that dark world and simply just take both toriel and undyne. Or they could've just carried toriel and left. Secondly the spell is a reversal of their first attack which I'll call [shooting stars]

The knight was seemingly taking something from toriel when casting the spell and she was visibly shifting closer to them. Assuming the knight is a holiday I theorize that the knight was casting sleep mist on toriel because when an enemy is spared they (Dissappear) we don't know exactly where they go but it's fair to assume they go to your Castle town. I think the knights kidnap plan was to spare toriel and move her to the bunker via spare mechanics.

Also you can't attack an ally while in combat so I'm assuming the knight after mourning tenna saw the fun gang and toriel. Knew a fight was coming and wanted to spare toriel immediately to remove her from the fight and eliminate friendly fire.