Cardfight!! Vanguard features a world where the game Cardfight!! Vanguard is becoming the latest craze among trading card games, becoming a part of everyday life for people all over the world. The game is not limited to Earth alone; battles between the creatures used by the players take place on another planet called Cray. The story begins with Aichi Sendou, a timid middle schooler whose meek attitude often leaves him a target for bullies. Aichi was given a very rare card, "Blaster Blade", when he was very young. It's his one treasure that gives him hope. That is, until it gets taken from him. Although Aichi has never played Cardfight!! Vanguard before, he challenges the thief to a game in order to win the "Blaster Blade" back. This high-stakes game quickly draws Aichi into the world of Vanguard battles, which will test and change his worth as both a player and a person.

One day, a huge UFO spins over Japan and crashes into a rural farmland outside Nagaoka, disrupting Tsubasa Misudachi's ordinary life. As the Gatchaman, the legendary defenders of Tachikawa City, supervise the ordeal, a peaceful alien creature emerges from the spacecraft. In the ensuing chaos, Tsubasa is given a special high-tech notebook, or NOTE, from Gatchaman founder J.J. Robinson, signaling Tsubasa's sudden recruitment into their group. Under the tutelage of fellow hero Hajime Ichinose, Tsubasa slowly begins to adjust to life as a defender of justice. Meanwhile, the CROWDS technology, which enables users to manifest their consciousness' into a physical form, is spreading amongst the public, as well as being endorsed by Prime Minister Sugayama. However, a mysterious organization known as VAPE has gained notoriety by using unique red CROWDS to wreak havoc, shifting public opinion against the CROWDS technology. The Gatchaman, along with new recruit Tsubasa, must put a stop to their destructive activities before it's too late. [Written by MAL Rewrite]

The four princes of Grannzreich—Kai, Bruno, Leonhard, and Licht— continue to compete for the right to their kingdom's throne under the guidance of their beloved royal tutor, the competent yet childlike Heine Wittgenstein. One day, during a political visit to Grannzreich, the king of the neighboring Romano Kingdom arrives at the royal palace with his twin sons, Ivan and Eugene. In the hopes of befriending the twins, Heine and the four princes meet their visitors, but their efforts are thwarted instantly when the two twin princes declare that they refuse to address those who will never reach the throne. Dispersing the tension between the boys, Heine reveals that he, upon their father King Victor von Grannzreich's request, will be tutoring the Romano princes alongside the Grannzreichs for the duration of their stay, in hopes of strengthening the future relations between the two kingdoms. [Written by MAL Rewrite]

Nine regular humans from different parts of the world are abducted and transformed into cyborgs with astounding powers for the purpose of being used as weapons. The nine cyborgs rebel and start to fight against their creators in the name of justice and world peace. Decades later, the nine cyborgs seem to be untouched by time, but they live in a world where "justice" has as many nuances as the number of people living on the planet. What is their place in the world now? "In the beginning was the Voice, and the word was Him; and all obeyed His word in great awe. But those who dwelt upon the land, through vanity, cunning and greed, attempted to build a multitude of towers whose tops reached unto heaven, and accumulated great wealth on earth. Scattering across the land and laying it to waste, man turned a deaf ear to His Voice. So He gave unto man an opportunity to atone for his misdeeds; and flame and smoke and the roar of a lion descended upon earth; and shattered the many towers to dust...."