Second Chance (Undertale x Gravity falls Crossover) (Stanley pines/Dream sans)

Stanley Filbrick Pines, or Stan for short, had already lived a hard, chaotic life. In the end, he died as he lived-fighting for his family. When Bill Cipher clawed his way back into the world after Weirdmageddon, wearing the body of the poor fool who'd once struck a deal with him, Stan knew what had to be done. He outsmarted Bill one final time, but at a terrible price. With a gun pressed to his head, he pulled the trigger, ensuring Bill's defeat-but sealing his own fate.

Ford was there, cradling his twin, desperately trying to save him. But it was too late. The life of Stanley Pines, the man who had tricked the dream demon and shielded his loved ones, was finally extinguished.

Or so it seemed.

Fate and Destiny, ever-mysterious forces, weren't finished with him. Death was not the end for Stan, it was a doorway. When his eyes opened again, he wasn't in the afterlife, nor the world he once knew. He found himself in a new body, a child's body... fragile, skeletal, yet brimming with light.

Stan had been reincarnated as Dream Sans, guardian of positivity, in a strange and unpredictable multiverse known as Dreamtale. For the first time in his many lifetimes, he had a chance to start fresh-with a new purpose, and even a new older twin brother by his side.

The man who once called himself Stan Pines now carried the mantle of a guardian, standing at the edge of countless worlds, ready to face whatever destiny of fate had in store.

Note: Some written portions here are made by ai in rewriting, but other myself, and the story idea was really in my head as I like to what this what if of Stanley pines reincarnated as Deam sans.

Also, the original idea of a similar story came from @KarmaAskabane425 go check out their, it's a good story.