They say that if you're still single at thirty, you'll become a wizard.
As an eighty-year-old wizard, he once swore a terrible oath: "If I ever fall for a woman, may I be struck by lightning."
Then he watched the new anime The Journey of Elaina and fell in love with the heroine, Elaina.
Does falling for a fictional character count as falling in love?!
So he was struck by lightning and died. He transmigrated, and "he" became "she," a little girl with white hair and red eyes.
In short, this is the story of an eighty-year-old white-haired girl traveling through time and space in search of her first love, Elaina!
Overpowered protagonist, infinite worlds.
The Journey of Elaina is a recurring world. The worlds that follow are Re:Zero − Starting Life in Another World, A Certain Magical Index, Arknights, Fate/Zero, Puella Magi Madoka Magica, Genshin Impact, JoJo's Bizarre Adventure Part 2, Demon Slayer, JoJo's Bizarre Adventure Part 3, Date A Live, JoJo's Bizarre Adventure Part 4, Black Bullet, JoJo's Bizarre Adventure Part 5, and Grimoire of Zero.
(Even if you haven't read the original works, you'll still understand!)
(There are fan interpretations and major changes, so please don't argue about the canon. Thanks!)