High above the realm of man, the gods of the world have convened to decide on a single matter: the continued existence of mankind. Under the head of Zeus, the deities of Ancient Greece, Norse mythology, and Hinduism, among others, call assembly every one thousand years to decide the fate of humanity. Because of their unrelenting abuse toward each other and the planet, this time the gods vote unanimously in favor of ending the human race. But before the mandate passes, Brunhild, one of the 13 demigod Valkyries, puts forth an alternate proposal: rather than anticlimactically annihilating mankind, why not give them a fighting chance and enact Ragnarök, a one-on-one showdown between man and god? Spurred on by the audacity of the challenge, the divine council quickly accepts, fully confident that this contest will display the utter might of the gods. To stand a chance against the mighty heavens, Brunhild will need to assemble history's greatest individuals, otherwise the death knell will surely be sounded for mankind.

After the death of his parents, a young Mirai Kakehashi is left in the care of his abusive relatives. Since then, he has become gloomy and depressed, leading him to attempt suicide on the evening of his middle school graduation. Mirai, however, is saved by a pure white girl named Nasse who introduces herself as a guardian angel wishing to give him happiness—by granting him supernatural powers and a chance to become the new God. In order to earn the position, he must defeat 12 other "God Candidates" within 999 days. Soon, Mirai begins a struggle to survive as a terrifying battle royale erupts between himself and the candidates looking to obtain the most power in the world.

Ever since moving to an in-game world after countless hours of VRMMO grinding, Yuna now calls Crimonia—the city where she started—home. While maintaining her reputation as a renowned adventurer, she continues to manage her businesses; but most importantly, Yuna spends time with the people she has grown to love. Nevertheless, this world has a lot more to offer the carefree adventurer. It is up to Yuna to discover these wonders, and perhaps help more people in need as she encounters their various plights.

Fourth season of Aggressive Retsuko.