About those PTPs, do you theorize that their niaeve and innocent act, is just that, an act to fool the unsuspecting masses? And do you also theorize that they're masters of guilt-tripping, and manipulation? And are they excellent liars? Could/would they ever snap, and snap someone's neck to end them? Let's discuss the levels of their jealousy, and possessiveness. Maybe, they are the most fearsome of monsters.
Okay, while I am not opposed to having something like that in a story aspect, I don’t believe that is how they behave.
Sure, as a general idea, they’re sweet, kindhearted, and loving. However, Papyrus has one in-game line that I feel perfectly sums up how the PTP’s function.
“W-WELL, THAT’S NOT WHAT I EXPECTED... BUT... ST... STILL! I BELIEVE IN YOU! YOU CAN DO A LITTLE BETTER! EVEN IF YOU DON’T THINK SO! I... I PROMISE...” - Papyrus (taken from the Undertale Wiki webpage on Papyrus under the quotes section) in a genocide route after being killed.
PTP’s are forgiving to a fault. They want to see the best in others and in themselves, that is the core value that runs through each of them, even if being in a Fell Verse has tainted it. I don’t see them naturally as being manipulators, liars, murderers, or anything like that. Sure, UF Papyrus and SF Papyrus have LV on their souls, but they didn’t want to make that choice in the beginning, they wanted peace.
I’ve mentioned in another post that I don’t do yandere, overly possessive, or manipulative skeletons. It’s not in my realm of comfort, for one, and I don’t think any of the bois function in that way.
Do I think PTP’s are naturally naive and innocent? Not necessarily. Do they always act like they aren’t naive? No, but they are incredibly smart and crafty, despite how they seem to other people. They can guilt trip if absolutely needed, but why do that when you can talk to the person you’re trying to guilt trip and convince them to change their ways?
Point is, the PTP’s are not manipulators, liars, guilt trippers, and all of that. They are incredibly smart, talented, and know a lot more than people think they do. Just because they are enthusiastic about something they like does not mean they are children or should be treated as children.