- Akashi - Gozen's bodyguard and cook at Susanoo's Diner
- Daimon Kiyota - Leader of the Korinto-kai
- Gozen - Demon-slaying samurai and leader of the Jingu Clan; love interest of Richard Sonnac.
- Harumi Nakahara - aka "NeuromancerQueen99", "Rum"; Teenage hacker living in Hyakumonogatari Heights with her brother Yuichi
- Inbeda - Leader of the House-in-Exile Oni; obsessed with money, revenge on family, and the erotic charms of Kiersten Geary
- Jake Hama - Private investigator working for Masao Tanaka, sidelines in blackmailing Love Hotel patrons.
- John - The Black Signal; former Morninglight recruit and former human John Copley, deified nastily by the Tokyo Disaster.
- Jung - Powerfully telepathic child left behind at abandoned Orochi school, also known as "Subject 28"
- Kaidan Refugee - There are many of these in Kaidan, but one on the second floor of Susanoo's Diner will talk to you
- Kaoru - former lover of Ricky Pagan, Phoenecian agent and current manager of The Dream Palace love hotel
- Mask of Kan'ami - acerbic sentient mask worn by Inbeda, comprehensive translator and skilled psychic tracker.
- Naonomi Tanaka - aka "Butterfly88" Morninglight recruiter at the Fear Nothing Foundation; Daughter of Masao Tanaka.
- Ricky Pagan aka Ruichi Sawamura - Rockabilly protector of Ginpachi Park empowered by Gaia, Amaterasu, and Elvis.
- The Rabbit Killer - Hop, hop, die!
- Yuichi Nakahara - older brother of Harumi, trivia-obsessed hikikomori and escaped recruit of the Fear Nothing Foundation
- Amaya Yu - Online friend of Harumi, former Orochi Group employee
- Masao Tanaka - Father of Naonomi Tanaka, government spokesman and quarantine manager, disbeliever in the occult.
- Azuma Kobayashi - Assassination target of Inbeda taken out first by The Rabbit Killer.
- "darkdeathevilman" - The online handle of a friend of Harumi
- "flashygurl27" - Another online friend of Harumi
- "phattrax" - An online friend of Harumi
- Kaidan City Mall
- Zeroes Wild Pachinko - Pachinko parlour
- Susanoo's Diner
- Jigoku no Yu Bathhouse
- The Dream Palace
- Hyakumonogatari Heights
- The Peony Lantern
- Orochi Housing Projects
- Orochi Tower
- Happy Smiles Kindergarten
- Shinto Shrine
- Yasuraka House
- Ginpachi Park
- Kita Pier
- Hamani Cemetary
- Quarantine Wall
- Manticore Plaza
- Midoru Market
- Nagahama District
- The Maiden Shrine
- Kaidan Map - The in-game region map player characters look at
- Kaidan Minimap - The less stylized inset minimap
- Kaidan missions - A list of all missions to be found in the zone
- Kaidan Billboards - A collaborative guide to Kaidan's billboards, with translations and location data.
Specific to Kaidan
Kaidan, plus the rest of Tokyo
- Kaidan Zone Monsters - A list of monsters found in the zone