WARNING: the following contains spoilers for Episode 8 of The Day I Became a God, now streaming on FUNimation.
The mysterious girl calling herself "Odin," AKA Hina Sato, has warned Yota Narukami that the world will end in 30 days. She will help him realize his hopes and dreams with what precious little time he has left. By now, though, it's likely that Hina is the one who is running out of time.
Hina has been accepted into the Narukami household, and one night, just days before the supposed apocalypse, Hina dreams of her beloved grandfather, who marveled at her growth, then promised to send her to a new family where she can grow up. She never saw her grandfather again, but it won't be too late to see her father again.
A Strange Family Reunion
Hina/Odin has been working tirelessly to make her new friends happy, and Yota returned the favor when he rescued her from getting trapped in a reefer truck during a festival a few days ago. Now, Yota is ready to help Hina again, especially since he now knows the truth of where she came from. She certainly didn't come from Asgard. Instead, she is the granddaughter of Mr. and Mrs. Narukami's old professor and mentor, who were asked to help raise her since her father had given her up. Armed with this knowledge, he looks up Hina's father and finds his residence on an online map, near the coast. Yota has helped his friends revitalize their ramen shop and move on from grief; now it's Hina's turn once again, and Yota and Odin begin their adventure.
On that hot afternoon, Yota and Hina arrive at the Sato household, where they meet Toshitoku Sato and his new wife. Once Yota explains who Hina is, Toshitoku and his wife are alarmed, and Toshitoku takes Yota and Odin to the beach early that evening to explain it all.
Hina had been born with Logos Syndrome, leading to cerebral atrophy as well as neurogenic muscular atrophy. There is no cure, and Toshitoku was sure that Hina wouldn't live much longer. But then she miraculously became better, and she was given to a new family. Toshitoku is delighted to see Hina doing so well now, but it's also bittersweet, because she is living on borrowed time, and the miracle will soon set like the sun. Troubled, but not discouraged, Yota says good-bye and heads back home with Hina, stopping at a hotel for the night.
The Emerging Picture
Given how Hina stubbornly sticks to her "I'm Odin from Asgard" story, she may be in denial of her tragic situation, or she may be terrified to have anyone else learn the truth and pity her. Hina doesn't want the truth distorting her life. Instead, she maintains an air of mystery so she can focus on her real mission -- to help as many people as she can during her last days. Hina's mission from the very start was to turn Yota's life around and help him win the girl of his dreams, Kyoko Izanami, and extend similar favors to Yota's friends. Hina is a gentle soul, despite her bratty attitude, and this may be her way of repaying the Narukamis for taking her in so graciously.
Suzuki's arrival at the Sato household later that night also suggests that there is a conspiracy afoot. This young detective has been looking into Dr. Korogi, who likely has a connection to Hina, and Dr. Korogi's work may explain Hina's health miracle and her apparent ability to see the near future. The big picture isn't quite fully exposed yet, but there is little doubt that advanced medical science and/or computer tech has granted Hina the temporary powers of a god, all in one little package. For all Yota knows, he's in for yet another miracle.