HP Kills the Dark Lord and Becomes the Dark Lord!

[Completed+HP parent generation+Fantastic Beasts and Where to Find Them+child generation+CP from time immemorial: Severus Snape OOC warning! Mountains of private facilities! Dongfang Yilan accidentally dropped into Hogwarts and met a bat with a hard mouth and a soft heart. The journey home is always difficult, and 3 billion years is not enough time to defeat Oriental Ylang. It's just that there are always accidents when traveling through time. The first time I met Snape who was eavesdropping, the second time I lost my memory and went to school with Snape. Dongfang Yilan, who has lost her memory, frantically absorbs knowledge and saves the young Sifu. The third time back to when Dumbledore was young, Ariana was not supposed to die. The fourth time, Hogwarts a thousand years ago was really shocking, but unexpectedly brought Snape. In the end, the cute little bat grew up, and Dongfang Yilan was pressed against the wall: "So this is the truth behind your amnesia and disappearance?" The Dark Lord is resurrected, how can he make Severus suffer, kill him and return to the wild world! Wait, something seems wrong? Is this world really the original world?