The National Defense Divinities (必殺の霊的国防兵器 Hissatsu no Reiteki Kokubou Heiki, Deadly Spiritual National Defense Weapon) are a group of powerful, mainly Special Fusion - only demons in Shin Megami Tensei IV.
They are deities of Japanese origin who wish to save the country and its people, having pledged loyalty to the nation. Omoikane states them all to have been souls who did great deeds for the nation in the past, becoming spirits of national defense to defend it later on as their reward. They were originally part of the Counter-Demon Force 25 years ago, but over time Tayama and the Ashura-kai obtained the mediums of six of them, forcing them to work for his group as well as be revived as many times as Tayama wishes. They despise Tayama and his organization, but are unable to act against his will. Each one turns into a huge stone slab upon defeat.
Koga Saburo, the first one to be met in combat, is met outside Club Milton in Shibuya; the Ashura-Kai seize his medium upon defeat. The next one is Tenkai, who guards Midtown and must be destroyed to advance. Following Tenkai, Yaso Magatsuhi prowls within Reverse Hills Building; attacking and defeating him is optional when revisiting the facility after the events of the Samurai's first visit.
If following Lilith's path, the last three Divinities under the Ashura-Kai are confronted at Camp Ichigaya, after a brief scuffle with a revived Koga Saburo. Michizane and Omoikane seal the path to the Yamato Perpetual Reactor and Yamato Takeru serves as Tayama's personal bodyguard.
In either route except for the White Ending, after the events of Infernal Tokyo, the Master Samurai formerly held captive by the Ashura-Kai in Roppongi Hills will seize the mediums of whatever Divinities were defeated before the activation of the Reactor and hand them over to Flynn when talked to there.
In the Neutral Route, Skins will present Masakado's Katana, the single medium not to ever fall into the hands of the Ashura-Kai, to Flynn, after a meeting at Cafe Florida. Skins then issues the instruction to unsheathe it in the main crossroads at Ginza to reawaken Masakado.
To unlock each Divinity for fusion, each of the stone slabs must be visited with the adequate medium in Flynn's possession. Due to this and to Lucifer Palace superimposing upon Camp Ichigaya, only Yaso Magatsuhi (optionally, if confronted in Reverse Hills before the activation of the Reactor), Tenkai, and Koga Saburo are unlockable in the Law path. Six Divinities are unlockable in either Chaos or Neutral paths, and the seventh, Masakado, is exclusive to the Neutral path.
- Yamato Takeru: Tayama's personal demon guard, confronted in Camp Ichigaya. He is controlled with "Yaizu's Flint."
- Yaso Magatsuhi: The only optional one amongst the group, confronted in Reverse Hills. His sweet smelling gas is used to produce Red Pills. Controlling him requires the medium "Hades Soil."
- Omoikane: The Wisdom General, one of the two Divinities defending Camp Ichigaya's lower levels. One must possess "Yagokoro's Brain" to control him.
- Michizane: The Thunder God, the second Divinity defending Camp Ichigaya's lower levels. "Tobiume's Shoot" is what allows control over him.
- Tenkai: The guardian of Midtown. He is controlled by the medium "Myoko's Disk."
- Koga Saburo: The newest member to fall into the Ashura-kai's possession; Tayama obtains "Ryoja's Scales," his medium, after Flynn defeats him. Said to have butchered countless Gaeans during the war between them and the Ashura-kai for Camp Ichigaya. Is confronted in both Club Milton and in the underpass between Shibuya and Ichigaya.
- Masakado: The Guardian of Tokyo who became the ceiling along with the young man who slew him. The medium that controls him is his katana. The slab holding the remnants of his power is at the Crossroads in Ginza.
- They are implied to be the same demons Take-Mikazuchi speaks of in his Challenge Quest concerning demons summoned during a great war one hundred years ago.
- Out of all of the Divinities, Masakado is the only one to,have a more powerful form: Fury Masakado's Shadow.