I've just realised that Ralsei's spell being called "Pacify" potentially houses a double meaning - one which strengthens his connection to Kris and the Dreemurrs.
Obviously, the spell's function is to "pacify" TIRED enemies, and in that sense it does exactly what it says on the tin. But to pacify is also to soothe, to appease, to subdue. And this is something that Ralsei is always attempting to do, particularly when it comes to Kris. He constantly reassures them, offers to give gifts or perform services for them, and most tellingly of all, sweeps troubling concerns under the rug in exchange for nice-sounding but ultimately meaningless platitudes. He does all of this in an attempt to keep them onside, to keep them behaving and to keep them doing what they need to do.
Think about how we use the term "pacify" in our lives. Generally we use it in relation to young children and infants - in the US, you literally have an object called a pacifier to soothe troubled babies and toddlers. Now think about how such objects are used - they can bring comfort to a distressed child, but arguably their main purpose is to give the parent(s) a means to make that child behave, to render them docile and passive, to get them to comply, to grant the caregivers in that child's life a reprieve from their big and troubling emotions.
Once you understand this, Toriel giving the horned headband to Kris takes on a new and troubling context. On its surface, it seems like a cute, harmless gesture that affirms their desired identity as a boss monster, as a true member of the Dreemurr family. But think about it some more, and you realise that all she was meaningfully doing was deferring their distress, granting them a quick fix to soothe them but allowing the underlying issue to fester underneath.
It's hard not to infer that Toriel giving Kris the headband was more for her benefit than it was for theirs - she wanted them to feel safe and secure, but she either couldn't face up to the difficult discussions regarding their nascent species dysmorphia, or she didn't think it really mattered enough to do so. So instead, she PACIFIED Kris with a superficial object in place of the genuine understanding and patience they needed.
So. Is it any wonder that Ralsei turned out the same way? Is it any wonder that he takes the path of least resistance when faced with troubling issues that can't be solved nice and neatly in the present moment? After all, he is just continuing to do what he believes is his purpose - to Soothe Kris's troubles, to Affirm their identity and importance, to Subdue their distress no matter how painful or pressing it might be. THAT was the purpose which Toriel instilled in him when she gave the headband to Kris - to PACIFY is literally in his nature.
With all of this in mind, Chapter 3 is shaping up to be very, very interesting.
(these ideas were gleaned from this excellent post by @dyke-dreemurr which I highly encourage y'all to read if you haven't - essentially going over Toriel's well-meaning but inadequate parenting towards Kris. I also riffed on that post with thoughts of my own which I refined and made into this post here! Thanks for the inspo!)