This is a random fanfiction idea I had after reading the LOTM novel. What if there were a complete pathway for magic, and what would it look like? So, I decided to use the Harry Potter world as a starting point and later add different worlds as the story progresses.
As you have read in the synopsis, the story focuses on the character Scarlet, who initially decides to use her knowledge to learn magic early and leave the wizarding world after her O.W.L. exams. However, everything changes in her third year when, out of curiosity, she asks the Room of Requirement, "What is the pinnacle of magic?" The room answers her by providing the diary of Rowena Ravenclaw, one of the four founders.
The diary describes how Rowena attempted to see the pinnacle of magic and, with help from Salazar, devised the ritual recorded in the book, which, once performed, allows users to see the pinnacle of magic. The book also explains how seeing the pinnacle of magic—and realizing that other worlds exist with magic stronger than theirs—shook them to the core. Seeing the mention of other worlds, Scarlet considers using the ritual, if not to see the pinnacle of magic, then at least to glimpse the worlds described by Rowena.
After performing the ritual, she encounters an unexpected result: she cannot remember what happened after initiating it. All she knows is that an exquisite tattoo now appears on her left hand—a card depicting a woman made of starlight, with mysterious runes etched across her body, wearing a star-decorated dress. (AN: Look up Agatha Harkness from What If...? for the visual idea.) On the floor beside her is a message etched into the stone: "Try Not to Go Insane."