The trio do not often interact as a group, but separately, the three share many interactions.
The three share interactions when their class interacts as one, with which Gundham is usually seen with Sonia.
Sonia and Gundham share a majority of their onscreen time with one another. Sonia compliments Gundham's hamsters and causes him to blush, as well as choosing to investigate with he alone when they reach the Fun House. During the fourth trial, Sonia and Gundham often complete one another's sentences to argue for Tanaka's innocence. She refuses to believe in Gundham's guilt at first, even when he readily admits to it. During Despair Arc, the two show similar chemistry. They share interests in dark magic and the occult, as well as evidently enjoying one another.
Hinata and Sonia are also seen with a liking towards one another. Sonia chooses to sit next to Hajime on the roller coaster during chapter four, and Hinata consistently expresses that he has great respect for Sonia. Hajime states during his first meeting of Sonia that she has a mysterious charm he wishes he could stare at forever. He also describes her as regal and graceful. Both are also two of the five survivors of the Killing School Trip. During Hajime's free time events with Sonia, they grow especially close. At the conclusion of their optional interactions, Sonia decides that Hajime is the hero from a Novoselican legend, declaring that the two of them are to be married upon the end of the school trip. This relationship only blossoms further during Island Mode, during which Sonia and Hajime begin to officially plan their relationship, and Nevermind refuses to leave Hinata no matter what happens.
Lastly, Gundham and Hajime, too, share chemistry. During the gameplay, Gundham is implied to have attempted to follow Hajime and Kazuichi Soda on their private adventure, denying his feeling left out and leaving hurriedly. However, Hajime expresses that he understands that Gundham was feeling left out. Hajime finds Gundham strange, and Gundham regards Hinata as a fiend with a 'low-level magical essence.' However, upon Gundham's death, Hajime, like Sonia, chooses to take Gundham's words and actions to heart, choosing to live on for his sacrifice. During Hajime and Gundham's free time events, Gundham and Hajime become close. Gundham shares his secret breeding techniques and backstory with Hinata, who seems glad to understand the breeder. At the conclusion of their free time events, Gundham offers Hajime his hand, an action only 'the singularity' is capable of. The two shake hands, Gundham insisting that Hajime is now unable to die without the express permission of Gundham alone. Hinata expresses that it had been a long time since he was so happy to be acknowledged by someone. During Gundham Tanaka's island mode, Gundham declares that he wishes to live the rest of his life with Hajime, referring to him as his 'soul's chosen companion.' He finally calls Hajime his friend, demanding that he assist him in demon beast synthesis for the rest of his life, before walking into the sunset with him hand in hand.
Hajime's separate closeness with both Sonia and Gundham, as well as the many canon hints towards Sonia and Gundham's affections for one another, the three were easily shippable as one pairing.
This ship was only fueled by the Free Time events and Island Mode content Sonia and Gundham share with he protagonist. Shippers believe that since all three share chemistry with one another, the pairing could definitely sail.
- Sonia and Hajime are the only two characters to cause Gundham to blush in canon (shown through sprites and description.)
- Sonia and Gundham have personalized dialogues at the beginning or end of Hajime's free time invitations.
- When initiating free time events, Tanaka receives a personalized text box: 'Can I really hang out with someone like Gundham?'
- Sonia possesses personalized dialogue when Hajime completes a free time event with her, stating: 'I probably don't deserve it, but it looks like Sonia and I grew a little closer.
- Hinadam refers to the ship just between Gundham and Hajime.
- Sondam refers to the ship just between Gundham and Sonia.
- Sonjime refers to the ship just between Hajime and Sonia.