Theory about Lila and Tsurugi clan
Hi everyone, English is not my first language so please excuse any formatting or grammar typos. The theory is based primarily on French and the order in which we learn Lila's names.
As many of us know, the Tsurugi's given names are direct references to the three sacred treasures of the Empress of Japan: Kagami is the mirror, Tomoe is the Magatama, and the name Tsurugi is the sword. But the given names represent two of the three treasures; the sword is missing.
What's interesting, however, is that the mirror and the Magatama must work together/join forces to defeat the sword and bring light back to the world.
All that's left is to find out who the sword belongs to... as you probably guessed from the post title, for me it's Lila/Cerise/whatever her name is.
In the myths, the sacred sword Kusanagi was discovered hidden inside the tail of a giant eight-headed serpent/dragon after it was killed (for the sake of this theory, let's say it's a serpent). At the beginning of the series, Lila is considered a viper who spits venom at everyone. The sword is still in the Rossi forge. Then, she "kills" Lila the viper to become Cerise Bianca; the blade is no longer in the serpent and becomes a white weapon. Then she becomes Iris Verdi (the iris has sword-shaped leaves, and in Japan, during the Iris Festival, children are given a wooden sword), the blade ready to cut the grass (potentially under someone's foot or Marinette's) just like in the legend. And finally, she becomes Saladin Martine, Saladin being known for the sharpness of his weapons. The name Martine also comes from "Mars," the Roman god of war. But it is also (at least in France) the name of a series of children's books that tell the adventures of an innocent young girl.
And Lila forges her identities as Tomoe potentially forged hers before her, and as Tomoe forged Kagami (physically and metaphorically).