Putting his life on the line, Willem Kmetsch leaves his loved ones behind and sets out to battle a mysterious monster, and even though he is victorious, he is rendered frozen in ice. It is during his icy slumber that terrifying creatures known as "Beasts" emerge on the Earth's surface and threaten humanity's existence. Willem awakens 500 years later, only to find himself the sole survivor of his race as mankind is wiped out. Together with the other surviving races, Willem takes refuge on the floating islands in the sky, living in fear of the Beasts below. He lives a life of loneliness and only does odd jobs to get by. One day, he is tasked with being a weapon storehouse caretaker. Thinking nothing of it, Willem accepts, but he soon realizes that these weapons are actually a group of young Leprechauns. Though they bear every resemblance to humans, they have no regard for their own lives, identifying themselves as mere weapons of war. Among them is Chtholly Nota Seniorious, who is more than willing to sacrifice herself if it means defeating the Beasts and ensuring peace. Willem becomes something of a father figure for the young Leprechauns, watching over them fondly and supporting them in any way he can. He, who once fought so bravely on the frontlines, can now only hope that the ones being sent to battle return safely from the monsters that destroyed his kind. [Written by MAL Rewrite]

Since the demise of the man believed to be Britannia's most wicked emperor one year ago, the world has enjoyed an unprecedented peace under the guidance of the United Federation of Nations. However, this fragile calm is shattered when armed militants successfully kidnap former princess Nunnally vi Britannia and Suzaku Kururugi, the chief advisor of the Black Knights, sparking an international crisis.

The powerful and untrustworthy Kingdom of Zilkhstan is accused of orchestrating their capture. To investigate, world authorities send Kallen Stadtfeld and her associates on a covert operation into the country. There, they encounter the immortal witch C.C., who is on a mission to complete the resurrection of the man responsible for the greatest revolution in history—a legend who will rise up, take command, and save the world from peril once again.

Fourth-grader Ayumu Fujino regularly draws four-panel manga for her school newspaper and is lauded as having the best artwork in her class. One day, she is asked by her teacher to turn over one of her manga slots in the school newspaper to a truant student named Kyomoto. When Kyomoto's manga pops up alongside Fujino's, it receives high praises for its detailed artwork, making Fujino furiously jealous. Refusing to be beaten by someone who barely attends school, Fujino devotes herself to learning to create manga. As time goes on though, her goal of outshining Kyomoto seems to only get further and further away, and Fujino, now in sixth grade, eventually gives up and quits making manga. Graduation day arrives, and Fujino is asked to deliver Kyomoto's graduation certificate to her. Through chance, the two end up coming face to face, and their unexpected meeting will end up having consequences far beyond what either of them could ever predict.

The second stage of the battle royale known as the Sekirei Plan is underway. Shintou Teito has been closed off; no Sekirei or Ashikabi may leave. Minato Sahashi and his harem of Sekirei must now prepare to fight new battles as changes to the rules are put into place. However, not all groups will return to the battle: some Sekirei are loved very much by their Ashikabi partners, who would rather forfeit the prize than see them perish. In the midst of the action, someone close to Minato may be more involved than he had ever imagined, and threats lurk around every corner. There are even rumors that the "Single Numbers," the most powerful type of Sekirei, have entered the fray. In the eyes of the "Game Master" Minaka Hiroto, everything is proceeding according to plan. [Written by MAL Rewrite]