A former gymnast, Aikawa Maki has turned her skills to a different way of life—street fighting. The only thing that truly makes her feel alive is violence. With amazing power and grace, she fights opponent after opponent, repeatedly demonstrating the gymnastic talent that earns her her nom de guerre, "Airmaster."

A summary of season one of Tensei shitara Slime Datta Ken with some extra content leading into season two.

When a hole opened up in the world and monsters flooded out, humanity prepared for the demon lord Rukimedes' rise once again. However, even the gravity of this situation cannot impede the antics of straight man hero Alba Frühling and sadist soldier Ross. Ross, trapped within a plane between two worlds due to Januar Ein's magic, encounters the demon lord taking a nap and looking far too comfortable in his confinement. Simultaneously, Alba, once again in prison, has been sidelined in favor of his eccentric companion's hijinks. Although separated, Ross and Alba continue their attempts to prevent the demon lord's resurgence, but unbeknownst to them, a ghost from Ross' past may just threaten their quest's success. [Written by MAL Rewrite]

Once upon a time, the demon lord Rchimedes spread terror throughout the world, until he was eventually sealed away by the legendary hero Creasion. Since then, a thousand years have passed peacefully. However, a mysterious hole has opened up between the demon and human spheres, and countless demons have surged into the human realm once more. Coming to the conclusion that Rchimedes would soon return to wreak havoc, a human king summons the possible descendants of the legendary hero—all 75 of them. Unfortunately, after so long, it was too difficult to pinpoint his true descendants. Among the lionhearted prospects is the amateur adventurer Alba Frühling. His skills may not be top-notch, but he is accompanied by the talented soldier Ross, who helps the young hero whenever he is in a pinch...or at least, he is supposed to. Though undoubtedly a skilled warrior, Ross is actually both sarcastic and sadistic, and hence revels in Alba's suffering. Senyuu. is a comedic adventure following the unlikely duo as they struggle in their endeavor to defeat the demon lord, meeting various eccentrics along the way. [Written by MAL Rewrite]