The second of the Four Horsemen of the Apocalypse, named War. He represents war, and his red horse symbolizes blood. He holds a sword to represent battle. He takes peace from the Earth and allows men to kill one another.
"One of the four horsemen of the apocalypse. He rides on a red horse and holds a great sword. He has the power to take peace from the earth and make men to kill each other."
—Shin Megami Tensei III: Nocturne Compendium
Note:Significant plot details follow.
Red Rider appears as one of the Candelabrum holders sent by Lucifer to test the Demi-fiend, possessing the Candelabrum of Insight. He first appears with the other Horsemen of the Apocalypse when the Demi-fiend first ventures into the Third Calpa. After defeating White Rider, Red Rider will appear outside the Terminal in the Great Underpass of Ginza. Defeating the Red Rider in battle will get the player the Candelabrum of Insight.
After being defeated and once the player reaches level 55, Red Rider can be fused in the Cathedral of Shadows on the New Kagutsuchi phase if the player possesses a Deathstone, a special item found only in the Labyrinth of Amala. Red Rider can be fused by any combination of demons resulting in a Fairy.
Red Rider appears as the summon orb boss of the Suginami Tunnels silver-level instance. He also appears as a boss within the Chain of Curse Deep Docks instance and a boss of the TR-Route of Denshi Kairo, through which the ability to fuse him can be obtained. He is a special triple fusion of White Rider, Power, and Koumokuten.
Red Rider is one of seven fiends available to fight as an optional battle. He is found in Kasumigaseki, in the underground area that requires ID Card Lv3 to access; for this reason, he can only be fought on the Neutral route. He has a 1/256 chance of spawning behind the door that requires 100 Luck to open; if he doesn't show up, a message displays pops up saying that nobody is present. His Almighty-spam mode is set by Fire resistance. Defeating him awards you with a Soma, 10 of each incense, and the ability to obtain him through Special fusion.
Red Rider is fought alongside the other three in the Challenge Quest, Errand for the Apocalypse. Belial has sealed the four in a Domain found in Infernal Tokyo's Ikebukuro. They are far weaker than they are when encountered normally, that does not make them any less threatening. If Flynn makes any attempt to challenge them before accepting the quest, the Fiends will eject him from the domain. Completing the quest grants Flynn the Peacemaker, which is only surpassed by the plasma gun in terms of raw power.