When you look up at the sky, what do you see? A blue sky? Freedom? A hopeful future? The people of Tokyo see none of these. Instead, an ominous alien mothership looms overhead, engulfing the city skyscape. Three years ago, they came. The arrival of the "Invaders" sparked the greatest war humanity had ever faced—one that threatened to end the world. The Japanese government scrambled to fight the Invaders. Weapons were mass-produced, sparking controversy and pacifist movements. That day, everything changed. And yet, nothing has changed. Kadode Koyama and Ouran Nakagawa live their final days like they always have: going to school, playing with friends, and doing what any carefree high school girl would do. As they grow up they come to learn what it truly means to be an adult, in a world where adults seem to be demons who only deceive and destroy. They come to learn the real threat to humanity is not the Invaders, but humanity itself.

OVAs of History's Strongest Disciple Kenichi bundled with volumes 46, 47, 49, 53, 54, 55, & 56 of the manga.

The story opens on Pirate Zap's ship, where two of his crew, Bonnie and Max, are tired and want to escape, but unfortunately they have no money. Three children were being held captive on the ship overhear them. The eldest, Amanda, who's father was a pro treasure hunter, knows the whereabouts of a great treasure, and offers them a deal. If they help them make a clean escape, they could take all the treasure they wanted. They agree, and the five of them barely escape and make it onto a small island where they meet Luffy and his crew. Unfortunately they were pursued and Luffy and Amanda are captured and brought back to their boss, the head of the Bayan Pirates, who is also after the treasure. Now Luffy and the others must battle the Bayan pirates and find the treasure that Amanda's father had left for his children. Amanda, who has always resented adventure and treasure because her father was constantly gone in search for it, finally understands his feelings. (Source: ANN)

After the final downfall of the rogue Bakugan Naga, peace was brought back to Vestroia. With the help of Danma Kuusou, his companion Pyrus Dragonoid, and other Battle Brawlers, the Infinity and Silent Cores were combined and the realm was recreated. However, New Vestroia will not be given any respite as humanoid alien invaders, the Vestals, arrive and conquer the Bakugan world in one fell swoop. Armed with a fearsome machine capable of restricting Bakugan into their ball forms, they aim to enslave the race as a form of entertainment. Now, the only force standing in their way is the Bakugan Battle Brawlers Resistance—a group of humans, Bakugan, and Vestals who oppose the idea of annihilating a sentient race. Led by Danma, they must venture into enemy-occupied New Vestroia and repel the invaders, to assure the survival of the entire world. [Written by MAL Rewrite]