How would Papyrus act, if he didn't suffer from dementia? Would he become something like Sans, a terrifying hunter that holds a good side for his loved ones?
Sans only retained what he has left of his sanity by removing himself from his soul completely. The corruption of the Hunger is too much to keep a stable mind and remain connected to the center of your being, so instead, he chose to close himself away from nearly all emotion. Only what he feels for his family remains now, and even that is warped, at times.
Papyrus would not be able to do that. He loves and cares too deeply, and without his willful delusions, he would lose his mind entirely, and likely either have to be killed, or perish on his own from the trauma of the corruption.
Chapter 16: Too Many Eyes
https://archiveofourown.org/works/20857010/chapters/62634868
There exist in this world things beyond comprehension.
This is a statement of fact, for objects and creatures and
concepts that can have no definition, purely by their own design. Things
too dark to see, even in brightest day. Too complex to know, even with
the greatest of minds. Too rotten to ever cure, with all the medicines
in science.
They obey only their own basest nature, as a starving animal
attacking without provocation, an insect invading another’s body to
raise its young… darkness falling in lieu of day. They cannot be called
evil, though the mind is given to attempt to name them, to put at ease
the fear it cannot understand but knows to be true.
It could be argued that the creation of what now dwelled in the
darkness of its own mind had been evil, that what brought rise to the
desecration and destruction of the world of monsters had been hardness
of heart and cruelty unbound. Loneliness and fear can turn a heart to
stone, after all… bring about acts both unthinking and malicious.
Perhaps it would even be right, to say Flowey had been evil, to desire the conquest and power that he did, to whatever end.
But the creature that remains, all that is left of his foolish
lust for control, is not evil. The fiend with a thousand eyes is naught
more than another beast clawing for existence in the muck and grime of a
world once good and loving and whole. He is a wreckage, devoid of much
of the power he once coveted so dearly, and a horror to look upon, all
majesty he might have born molded and decayed.
He had hoped to become a god. And with the power of the souls he
had stolen, he had ascended… but into an amalgamation of what his
twisted desires had made him into, a mind of metal, unfeeling and cold, a
pile of vegetation both prickly and vile, an abomination that saw all
but learned nothing from it.
As he slowly rotted in the prison of his own making, his form
only twisted further. His hunger was unending, and his savagery a
monstrosity to behold. Yet the more victims he took, the hungrier he
became, and the more he was polluted, the stench of bloated corpses and
fetid meat enshrouding his gargantuan, wilting, rusted facade. His mind
was just as spoiled as his body, both a temple to his own vile glory and
a black hole of self-hatred, perpetuated by both of the people he had
once been.
The flower within him screamed unending
for vengeance, for the death of the human that took his power in the
first place but had escaped him… for the pain of his existence to end at
last. The prince cowered and wailed for his mother, for his best friend
and for someone, anyone to save him.
All he had wanted was to feel. And now, all he wanted was to never feel again.
His very existence was a crime, an unholy
being that persisted despite all reason. His hunger was unfathomable,
and defied every attempt to assuage it. His mind was a trap of the worst
kind, all knowledge but pain and hatred and starvation and fear escaping it.
He craved the end as fiercely as he clung to life. He hated his existence as ardently as he loved it.
He called for help, in the desperate misery that he had created himself…
And no one came.
hE rEAllY WaS An iDIot.