Harry Potter: After Betraying Grindelwald, I Ran Away Pregnant

[A quick note: I'm a Dumbledore dream girl, so please don't read if you dislike Dumbledore/Grindelwald]

[The groveling ex-chases-his-wife trope + running away while pregnant + my nemesis is my destiny + a transmigrated woman from the 21st-century Wizarding World]

When a transmigrated fan becomes the white moonlight's cinnabar mole, I clash with the Dark Lord and run away with my daughter.

After transmigrating, Lin Xi managed to win the favor of the young Dumbledore. But through a cruel twist of fate, she indirectly caused a family tragedy and was also tricked by the For the Greater Good. Heartbroken, she fled with a child in tow, and in the process became the most troublesome mysterious opponent on Grindelwald's path to power.

One hundred years later, at Hogwarts.

Looking at the old headmaster blocking the doorway, his eyes burning and his beard as disheveled as his hair, she glanced at the newspaper headline announcing his impending duel with the Dark Lord. Lin Xi gracefully raised her wand.

“You want to acknowledge your daughter? Fine. Go take care of that blond madman first, then come talk to me about custody.”