In the ruins of the Shinjuku showdown, Sukuna, now flush with loan money, was about to give his acceptance speech when he saw a beam of light descend from the sky and land on Gojo Satoru.
Gojo Satoru kept growing taller and bigger inside the light. In the end, the one standing before Sukuna was a giant over fifty meters tall.
Sukuna: ?
Everyone watching the livestream fell into an eerie silence. Finally, Itadori Yuji stammered, "So... is Gojo-sensei a woman?"
That giant standing there looked exactly like a female Ultraman!
Dreaming of the stories of other Lights in a distant parallel universe, Jinia was absolutely delighted to have caught... ahem, acquired a human host as soon as she arrived on Earth. She spoke inside her host's mind: "With me around, I absolutely won't let you get bullied by the Defense Force or anyone like that!"
"Wow, that's really reassuring."
After a sigh of admiration, Gojo pointed to the collar around his neck and asked, "So why is your transformation device a collar?"
"That way, we don't have to worry about the awful possibility of your hands and feet being restrained. And it won't be so inconspicuous that someone might steal it without you noticing! Plus, this design makes it obvious that Light is the bond between us!"
So that's what you mean by the bond of Light?!
Gojo Satoru quickly accepted this setup and nodded.
"Then I look forward to working with you, Jinyao."
(Note: Jinia is pronounced as one combined name. When joined together, the final part, Nia, sounds like the Japanese "nya," the sound a cat makes, which is like "meow".)
There are many original settings and changes to the worldbuilding, mostly on the Jujutsu side. Ultraman from the TV series and movies will be mentioned, but generally won't appear, and they won't enter the TV storylines on the Ultraman side.
Theme: May you be a guiding light.