>>713035984
Personally when I attributed Jevil and Spamton going crazy to "Gaster" I didn't think Mysteryman literally swooped in and told them "YOU'RE IN A VIDEO GAME LOL," just that what we we're told about what happened has very clear "Gaster" marks on it. It doesn't mean that he personally intervened to make it happen, just that we're meant to connect it back to him.
>Jevil met a "strange someone" and turned Seam's view of the world "darker, yet darker"
>Spamton's phone call sounds like "nothing but garbage noise," aka "mus_smile" which plays in ENTRY NUMBER SEVENTEEN
Jevil went crazy and was locked away long before The Knight showed up, Seam's account makes that clear and identifies the "strange someone" as someone different than the "strange KNIGHT."
Spamton likewise had his fall from grace before the events of the story, and as far as we're told The Knight never actually entered the Cyber World. Moreover, Spamton wasn't given his Shadow Crystal, he found it in the NEO body, and dialogue from Seam and Swatch seems to explain that it naturally formed there rather than being placed for him to find.
I like the idea that The Knight is testing The Fun Gang's strength, I think that's the best explanation for why they give us a "fair fight" in Chapter 3 and why they summon the Titan in Chapter 4, but I don't think we have the evidence to say they're behind the Shadow Crystals.