The planet Remnant, several light years from Earth, is home to many young men and women who are willing to train to become Huntsmen and Huntresses, great warriors who combat the rampant evil plaguing the world. But what if something else made its way to this fantastic battleground, something more alien than even the Grimm? What if a symbiote landed onto Remnant?

Metal Sonic, the pinnacle of Dr. Eggman's robotic designs, has broken free from his creator's chains and now seeks nothing short of global domination. To that end, he has lured Sonic and his band of heroes into giving him everything he needed. In our time, Metal still despite his clever scheming. But here, the worst possible outcome has occurred. Metal Sonic has won.

Ruby Rose was but a small, honest soul, pure and indomitable by nature. Her life would change forever on a fateful night in Vale, leading her to attend Beacon Academy, where she would become one of Remnant's great heroes. But what if Ruby became one of the monsters she would learn to fight? Would she still be a symbol of hope, or devolve into a bloodthirsty creature of the night?

All her life, Ayano Aishi struggled with a serious mental condition that stripped her of her ability to feel, driving her to do anything that would cause her to feel like a neurotypical person. But what if her illness wasn't as serious as the doctors, therapists, and psychiatrists believed it was? Perhaps Yandere-chan still had a heart despite it being so... empty inside.