WARNING: The following contains spoilers for Rust-Eater Bisco Episode 12, "Bow and Arrow Duo," now streaming on Crunchyroll.
Rust-Eater Bisco's season finale brought one final twist as it wrapped up the battle against Kurokawa and the Tetsujin. The mission to stop Kurokawa may have reached its end, but the episode shows there's still plenty to be revealed about Mushroom Keepers and their abilities.
Episode 11 left fans questioning whether Milo was on the brink of death and if the sudden return of Bisco was nothing more than a welcome from the other side. This episode, however, quickly answered that question. It also gave fans the answer to just how Kurokawa was managing to pilot the Tetsujin. While it certainly seemed that his consciousness had somehow merged with the Tetsujin, it was revealed that both he and Bisco were actually alive inside the body of the monster.
Having been coated by the pipe-snake venom, Bisco's Mushroom Keeper blood reacted in a way that caused his body to take on the properties of a Rust-Eater mushroom, saving him from succumbing to the rust. Kurokawa, on the other hand, had made his way to the head of the Tetsujin, revealed later by Tirol to be the location of where the pilot would control it. Despite having been a former Mushroom Keeper himself, Kurokawa's body had instead become one with the rust. However, this meant that Bisco and Milo would finally be able to stop him due to the way his body would react to Bisco's newfound powers.
Now essentially a Rust-Eater, Bisco's newly regenerated arm is capable of producing countless Rust-Eater blooms with each arrow launched. While he can't control the size of the blooms, with Milo, Jabi and Pawoo's help, he is able to break through the Tetsujin's helmet to attack Kurokawa directly. With Kurokawa dead once and for all, the Tetsujin is finally stopped, no longer at risk of self-destructing and creating another Tokyo-sized crater or a second wave of the Rusting. Pawoo and Jabi are finally cured of their Rusting, fulfilling the goals both Bisco and Milo had at the start of the series. Nonetheless, even though Kurokawa is gone, there's still plenty left to be done for the city of Imihama.
Fit for what feels like the end of an adventure, the episode gives viewers a montage sequence showing the aftermath of the battle. Milo dispenses the Rusting cure to the population of Imihama, Pawoo takes over as governor of the city and separates from the rest of the Japanese government, the adults of Tetsujin Town return and lastly, viewers see Bisco's wanted poster now labeling him as "bomber" of the North Miyagi Great Plains Military Base. In her new position, Pawoo denounces the persecution of Mushroom Keepers, but with Bisco's brash methods and what appears to be a disjointed series of governments across Japan, his reputation as a wanted terrorist remains -- joined now by the "man-eating Panda."
By choosing to close with Bisco and Milo in disguise and remarking on their wanted posters at the city gate, Episode 12 pays homage to the first episode of Rust-Eater Bisco. It recalls Bisco's growth as a character as well as the growth between Bisco and Milo in their partnership. It all comes full circle when Bisco gives the gate officials the Rusting cure as thanks for having fed the mushroom he'd unleashed there at the very start of the series when they tried to arrest him. Although it's clear that Bisco and Milo are still going around the rest of Japan trying to clear out the Rusting, such a poignant ending to the series could suffice.
However, the episode officially concludes with Bisco and Milo heading off in search of a way to reverse Bisco's new powers and immortality, hinting that there's more story to come. There hasn't been an official announcement for a second season yet, but with the light-novel series still ongoing and the manga adaptation receiving its second part in December 2021, fans might still get a chance to see Bisco and Milo's next adventure on screen.
