Ichiro Sakaki
The deputy director of the lab. He was the protagonist's instructor at college and is now her superior.
- Affectionate Gesture to the Head: He tends to pat or stroke the heroine's hair throughout his route.
- Dark and Troubled Past: He lost his home at a young age. His purpose for his career choice to help as many islands as he can.
- From Roommates to Romance:: In his Sweet Ending, he and the heroine live in the same house, but they sleep in separate beds. The heroine then decides to seduce him.
- Lap Pillow: There's a scene where he allows the heroine to rest her head in his lap. She can attempt to do the same thing for him, but he'll decline, saying that he'd like to do it another time.
- Lecherous Licking: When the heroine gets melted chocolate on her fingers, he chooses to lick it off instead of using a napkin.
- She's All Grown Up: He notes how more beautiful the heroine has become.
- Student/Teacher Romance: Subverted as the relationship is older. He's the heroine former biology instructor.
- Sweet Tooth: He likes chocolate and is noted for liking sweets.
- The Tease: He likes to flirt with the heroine, much to her embarrassment.
Ryo Tsuzuki
One of the security guards at the lab.
- Bodyguard Crush: He's a security guard, not the player's bodyguard. However, if his route is selected, he will become increasingly more protective and more enamored with her.
- Curtains Match the Window: Red hair and red eyes.
- Dark and Troubled Past: He lost his father and older sister in a terrorist attack and his mother suffered from PTSD after the incident. As a result, he became a member of the National Police Force in order to prevent other people from suffering through a similar incident.
- Red Eyes, Take Warning: He'll go to great lengths to protect the heroine.
Ren Nishimura
A hard-working scientist.
Lionel Saito
Another security guard at the lab.
Keas
The secretary of the director.
- Guns Akimbo: He uses two handguns when fighting zombies or the heroine and her selected lover.
- Stoic Spectacles: It's hard to read his expression with his sunglasses on.
Shota Todomi
A local of the island. He's a relative of one of the island's elders.
- Declaration of Protection: Once the infection starts, Shota promises to protect the heroine however he can.
- Dogged Nice Guy: He obviously likes the heroine, but she pursues other guys. Poor Shota. This is played up even further in his route on the Story Jar. He very clearly likes the heroine more than just a friend, but he’s initially turned down because she doesn’t know how she feels about him.
- The Immune: Shota possesses some antibodies in his blood, which protect him against XH. Because of the heroine’s actions where she sucked out some of his blood (thinking he might have been attacked by something poisonous), she shares the same immunity.
- Innocent Blue Eyes: He has light blue eyes, which match his kind and trusting nature.
- Interrupted Declaration of Love: In Ichiro's Sweet Ending, he attempts to confess to the heroine. Unfortunately, Ichiro steps in and tells him that the heroine is his.
- Likes Older Women: The heroine is noted to be older than him.
- Meaningful Name: "Shota" means "young boy". While he's not that young, he's young enough for a noticeable age difference between him and the heroine.
- Nice Guy: One of the few islanders to welcome the player and the researchers.
- Reasonable Authority Figure: He's the only one the islanders will listen to.
- The Rival: In just about every route, he will challenge the selected love interest for the heroine's heart.
- Secret Character:
- Unfortunately, he doesn't have a separate route available for him. He does, however, have two holiday spin-off stories, which are placed under Ichiro.
- In the Story Jar app, you can actually pursue Shota in his own separate route.
