Peacetime (平穏, Heion) is the 1st episode of Heion Sedai no Idaten-tachi anime series.
Centuries ago, vicious and bloodthirsty demons who were immune to all manner of weaponry plagued mankind. Humanity's cries for help brought forth the Idaten; battle deities who would use their incredible speed to hunt the demons down, and then seal them away. In the following 800 years of peace, the Idaten have not had any enemies to fight. But that is about to change...
800 years ago, demons existed. Immune to modern weaponry, humanity was pushed to brink of extinction. Humanity then prayed and gods appeared, battle deities called Idaten. They quickly defeated the demons and sealed them. To ensure the safety and effectiveness of the seal, the Idaten sacrifice themselves, leaving only the young Rin to protect the seal and guide the not yet born gods.
At present time, Rin is training Hayato and tells him to go faster as she runs ahead of him. Annoyed she is faster, he insults her, but in an instant Rin turns around and starts beating him. As they finish the race, Rin complains that Hayato took nine hours to run around earth, which is slower than his usual. Hayato is angry and insults her reminding her that he was slow due to she beating him, however for insulting her again, he gets beaten once again. Rin tells him that he needs to be fast to be a proper Idaten and starts telling him about the demons, but Hayato, isn't interested in listening as he had heard this story before. He has been born for 80 years and the world seems peaceful to him.
Hayato goes to meet Ysley, who is reading a book. Hayato wonders why don't he train sometimes, but Ysley prefers not to and states that he loves studying and due to his long lifespan he can learn more than a human can. The two then go see Paula, scaring the birds she was with and annoying her. Hayato wonders if the birds told her something and Paula reveals they told her that humans had gathered by the glaciers up north and have giant green birds with them. Ysley guesses its the military transport airplanes of Zoble Empire. Hayato states that instead of wondering what they are doing there, they should just go check out.
As they reach the glacier, they see large group of humans and Hayato comments they can't get closer without being seen. Ysley asks Paula to go as she can move fast and quietly, and gives her a microphone so they can hear what the humans are saying. Oobami comments that they are almost done and Paula notices a large frozen demon, Gyudo-kun. Oobami explains the demon is a weak demon, but its more than enough for humans, but wonders if the gods had changed. Hayato is excited to see a demon that Rin talks about, however, Ysley wonders how Oobami know about the events 800 years ago. Hayato guesses he may have been alive for 800 years, but that's not possible for a human. Ysley then starts to consider that Oobami may not be human and is a demon who has been working on reviving the demonkind.
Gyudo-kun then breaks free from the ice and Oobami starts celebrating. He explains that Gyudo-kun is quite docile and if you don't provoke him, he won't attack, however, that's doesn't apply to gods and he will attack upon seeing them. Gyudo-kun then attacks, making Oobami wonder if there is something wrong with him, however, Paula manages to dodge his attack. The humans thinking it attacked them, start fighting back, but end up destroyed easily. Oobami then sees Paula and how Hayato comes and kicks Gyudo-kun, knocking him down, and making Oobami realize they must be Idaten. He gets excited to see if they had softened due to the peacetime. A human shoots at Hayato, but the bullets bounce of his head, only annoying Hayato. Gyudo-kun gets up and attacks Hayato sending him flying, and the blasts him off. Ysley then kicks Gyudo-kun, but it has no effect. Gyudo-kun pierces Ysley in the chest. As Gyudo-kun is about to end Ysley, Paula comes and kicks him, but as the kick is also weak, Gyudo-kun hits her and breaks her bones. As he is about to crush Paula, Ysley with a large hole in his chest, manages to get her and uses his speed to escape the demon. Ysley states that the demon is incredible though and powerful, but can't compare to Idaten's speed. Second, Oobami doesn't know much about them as he is surprised Ysley is still alive even without a heart. And third, while its strong, it shouldn't be a match for Hayato who trained under Rin. The ground rumbles and Hayato comes lifting a large piece of ice and tosses it at Gyudo-kun. Gyudo-kun prepares to catch it, but in that instant Hayato kicks him in the stomach, causing him pain and forgetting about the ice that then hits him on the head. Hayato proceeds to punch the demon and send him flying. As the demon gets back up, Hayato goes through him, piercing him and creating a large whole in his chest, killing the demon. Hayato expects the demon to get up, but gets surprised its already dead. Ysley realizes that if demons die from such injuries, then they are closer to living things than to them. Oobami flies off with a jet at mach 2, commenting that while he couldn't obtain Gyudo-kun, he got some nice data about Idatens. However, Hayato easily catches up on the jet and takes it down as he wants to chat with Oobami.
Ysley calls someone to come and retrieve the demon's body, before Zoble Empire is able to do the same. Hayato realizes that humans should die from a plane crash and goes to check on Oobami, but sees he is a robot, who to not let himself get caught, blows himself up.
Elsewhere, in a town turned battlefield, Zoble soldiers enter a church and see a young sister. She tries to tell them that God won't forgive them for their pillaging, but the men don't care and strip her and then violate her.