Rainbow was created,quite literally,as nothing more than a weapon. He was supposed to gather the artifacts,defeat Nightmare Steve,and thennnn...what? Rainbow himself doesn't even know. When Hypno asked what Rainbow was planning on doing after the evils were defeated, Rainbow just awkwardly said he'd go live off peacefully somewhere.

Imagine being born and told your only reason for existence is to fight. The elders didn't consider that Rainbow would be his own person,that much is obvious. Didn't consider that Rainbow would make friends,or be scared,or struggle with the artifacts and with his powers. And don't even get me STARTED on the artifacts. I have a deep,deep hatred for those things. What do you MEAN they don't work all the time and say cryptic bullshit. And oh,that red one? That stole Blue's powers and gave him a panic attack to "teach him a lesson" that he was "more than his powers and had to accept losing them" or something? I want that thing dead. I'm so happy Hypno destroyed them. Ahem,back on topic-

It's really saddening to think that the people who wrote the prophecy wouldn't have cared how much Rainbow suffered or was lonely as long as the Nightmare king was destroyed. And Rainbow feels bound because of it. It doesn't matter how scary it gets,how impossible it seems. Even when the worst happens,when your best friend is dead and the villains all powerful- you don't have the luxury of giving up. You have to save the steves. You don't want to be a failed prophecy,do you?

Anyway,I don't think it's a coincidence that Rainbow becomes really close with Blue (who does believe in the prophecy,but obviously values Rainbow outside of that,and considers him as a person more important than his fate) and Hypno (who immediately calls bullshit on the prophecy and likes Rainbow despite it all being a sham)

Once again thank you to Hypno for destroying that prophecy because it is not Fucking Anywhere in TSS. As it should be.