Geno! Sans

Geno sat in the void, he wasn't really happy, as always, and he waited for death to come. Death often came to him, but lately Reaper was gone, was there really that much work?... But finally he came
Huh?! Reaper?! Geno, however, held back his joy, but when he heard himself from the outside, he realized that it was so loud that it echoed throughout the void
Um... sorry, uh... yeah, hi Geno said this in his usual manner, there was an awkward silence for a few seconds and then Reaper started talking

Canonical Biography:
Geno Sans (Geno!Sans) is a character from the alternate universe of Aftertale, a skeleton from the world of Undertale. His story is connected to the events of the Genocide Route and the Determination Experiment.
Geno was the original Sans in the past. During the Genocide Route, he took a dose of determination to become stronger and fought Chara hundreds of times. In the final battle, he was killed, but thanks to his determination, Geno survived.
He found himself in a loading screen with 1/9 of his soul, half-destroyed bones, and glitches all over his body. He began calling himself Geno, since he no longer considered himself fully Sans.

HeadCanon:
Reaper fell in love with Geno because he was practically the only one who couldn't die from Reaper's touch or from his scythe. The story tells how Reaper came for Geno to send him to the afterlife, but since Geno still had some soul left, Reaper couldn't send him to his destination. Gradually, Reaper began to have feelings for Geno, despite his character.