HP Starts from the End (Snake Ancestor*v, Lion Ancestor*harry)

In the final battle, Voldemort and Harry were sent back thousands of years. By chance, Voldemort and Salazar Slytherin signed a binding contract with unknown conditions, and the two were forced to bind everything to each other, including life and magic. When Voldemort's memory is confused, how can the contract premised on binding conditions be untied? What are the constraints that bind a contract? And what accident would have happened to Harry when he was alone thousands of years ago? CP: SS×LV, GG×HP In all the fanfics, Voldemort conquers the wizarding world, why can't he be the one who accepts it? Other fanfics assign Little H to Big V, Professor, Little Dragon, etc. Why is there no Lion Ancestor? I think Snake Ancestor and Snake King, Lion Ancestor and Little Lion Head are the correct ways to open HP fandom! As well as Salazar attacking, Voldemort is suffering!! There will be a child! Strong! Motto: Live hard, and you will eventually be rewarded.