At the pinnacle of his gymnastics career, Joutarou Aragaki—nicknamed Samurai for his signature hairstyle—suffers a shoulder injury following his wife’s death. Five years later, he continues to push the limits of his body as a member of the Japanese gymnastics team. However, Joutarou's strenuous training fails to show any progress. His coach, Noriyuki Amakusa, advises that he retires. Together with his exuberant and supportive nine-year-old daughter, Rei, Joutarou takes a trip to Ego Wonderland to break the bitter news to her. However, their excursion ends in an odd encounter with a peculiar self-proclaimed ninja named Leonardo. He follows them home and interrupts Joutarou’s every attempt at telling his daughter. Upon learning that Leonardo hopes to witness his gymnastics again, Joutarou astounds Japan with his announcement that he is not retiring. With fervent support from his family, friends, and Leonardo, Joutarou dedicates himself to the biggest challenge of his career and prove that the gymnastics world is right where he belongs. [Written by MAL Rewrite]

The OVA will be bundled with the 7th volume of the manga, scheduled to ship on August 26, 2015. It will be a sea bathing episode. (Source: MAL News)

In the series' backstory, 102,000 years ago in a place that would be modern-day Mexico, it started with a mysterious but powerful race with incredibly long lifespans and the ability to absorb life forces from plants and animals, although they had the disadvantage of being easily disintegrated if exposed to sunlight and thus lived underground instead. Kars, an underground-dwelling humanoid being known as a Pillar Man, created a stone mask which grants immortality by absorbing life energy to conquer the sun (which kills his kind). However, the stone mask cannot penetrate his head and unlock Kars' true potential. As he tirelessly slaughtered things for blood to activate the stone mask, his tribe begins to fear Kars for his obsession. When his tribe says Kars must be killed, Kars is angered and questions them if they want to conquer the sun. If they objected, Kars would say they will die. As his tribe attempts to kill him, Kars and his companion Esidisi fight back. He slaughtered all but four of the tribe.

Second season of Muhyo to Rouji no Mahouritsu Soudan Jimusho.