An extremely honest person who tends to speak his mind, for better or worse. He is also bad at lying, leading Utsumi to frequently warn him to stay quiet, making him seem a bit reckless. Despite this, he seems surprisingly concerned about his reputation among others. Regarding his amnesia, while he finds the lack of memory inconvenient, he usually doesn't feel particularly anxious or rushed to recover it, being quite easygoing in a sense. However, as mentioned, his personality transforms from his usual mild-mannered self when a kaiju appears, becoming brave with a strong sense of justice (what the director calls "Part B Yuta"), leaving Utsumi bewildered by the change. On the other hand, he possesses the very ordinary mentality of a teenage boy, such as being deeply shocked when Utsumi joked that the kaiju might actually be humans. Because of his amnesia, many things are first-time experiences for him, so he can get excited like a small child over simple things like looking at a river from a train. He likes Rikka and wants to confess but can't quite bring himself to do it. He merges with Gridman to become Gridman. He is best friends with Guest.

Although he moved to a different class from Yuta in his second year, they remain as close as ever, with him giving Yuta romantic advice. He seems to have slimmed down slightly around the waist. He is in charge of the script for the class play at the school festival along with Rikka, and is even making the costumes himself. When Yuta has to merge with Gridman to fight again, he resolves once more to support him as part of the Gridman Alliance. The novelization reveals he still occasionally dreams of the sight of Yuta being stabbed by Akane, emphasizing his desire to never let Yuta be in danger again. His relationship with Hass seems to be progressing, as they meet up alone at a batting cage...? He is best friends with Guest.

Now a second-year student, she is in a different class from Yuta and Hass. She is handling the script for the class play with Utsumi, writing a story based on the days they spent in the Gridman Alliance. In the novelization, she explains the events of the past two months to the memory-less Yuta. She harbors complex feelings when Yuta merges with Gridman again to throw himself into battle. There are rumors that she has a boyfriend in college, but...?

Due to the influence of the mastermind, he was blown from Fujiyokidai to the Tsutsujidai of another world along with the other members of the Gauma team. Afterward, he reunited with Rex, who is the reincarnation of Gauma. Having carried the weight of their parting—which felt almost like a permanent death—he was moved to tears of joy. Male.

She wandered into Tsutsujidai with Yomogi (likely while on a date), and since it was a different world, they got lost not knowing the way. She met Rikka and joined up with the Gauma team. She ended up staying at Rikka's shop. In contrast to the fleeting and mysterious atmosphere she had in the main story of SSSS.DYNAZENON, she is quite high-spirited here. Seeing as she also fools around and acts energetic when spending time with her friend Mei, it seems this bright personality is her true self around those close to her. With her worries gone and having a boyfriend to gush about, her naturally upbeat nature has come to the surface.

She visited the batting cage to look for the missing Koyomi, but in the process, she wandered into the world of Tsutsujidai and encountered Utsumi. After explaining the situation, she reunited with Koyomi at Rikka's house and met Gauma, who was thought to be dead. While the anomalies were occurring, she helped with the preparations for Utsumi and Rikka's class play, showing off the drawing skills she honed through Zentangle art. The novelization depicts her helping with the scriptwriting as well, telling Rikka about her memories with the Gauma team. However, she was bewildered when Yume forgot that Goldburn had saved her when she fell from the sluice gate. When their attacks stop working against the mastermind, the paint on Chise's arm is given new form by a god's power, granting Goldburn a new appearance and bringing new power to Gridman.

Blown into the world of Tsutsujidai by the mastermind's influence, he suddenly appears in the bathtub at Yuta Hibiki's house. They encounter each other in the worst possible way—strangers and both naked—but he manages to clear up the misunderstanding and joins Chise and the others at Rikka's home, "Junk Shop Aya." There, he reunites with Gauma, whom he thought was dead. Since he has no place to live after the reunion, he ends up staying at Rikka's house along with the rest of the Gauma team and the Neon Genesis Junior High Students. During dinner, he showed considerable boldness by gulping down beer provided by Rikka's mom and sleeping soundly while Yomogi couldn't sleep due to the snoring of the other men.

His original name was Gauma. He was thought to have died but became one of the Neon Genesis Junior High Students. He has an optimistic personality. He is a reliable adult and the guardian of the Gauma team. On the other hand, he has a "take what you can get" spirit, unhesitatingly digging into the hot pot at Rikka's house. He can become Dyna Rex.

A kaiju appears in Tsutsujidai, a place where they were supposed to have vanished, and along with it, he visits this world again, merging with Yuta through the Junk. In doing so, he takes the form of Primal Fighter, essentially wearing the appearance of the Hyper Agent to adapt to Yuta. After capturing Alexis Kerib at the end of the previous battle, Gridman felt a sense of guilt for robbing Yuta of his memories and daily life for two months. This guilt was exploited by the mastermind of this incident, expanding the creativity and merging abilities Gridman acquired through contact with humans to their absolute limit. As a result, Gridman had become the universe itself. In other words, the Gridman appearing from the start of this story was something like an avatar.