Chapter 16 is titled "Star-Breaker".
Daruma takes Hachimaru and company into outer space to prevent the destruction of their home planet. However, he needs Hachimaru's help to get the job done. With Daruma's guidance, he learns to combine his willpower and the three sources of a samurai's strength in order to use a Kongo-Yasha move that can save his world. Once the planet is safe, he leaves his world behind to start his journey to become a fully realized samurai.
As Muun fall towards the planet it orbits, the public notices the danger. Meanwhile, the head princesses of the planet's Samurai Castles dispatch all of their available Samurai to try to destroy Muun before it crashes. The Samurai gather in their Holders and begin destroying the satellite's debris, but cannot keep up with the sheer size and number of smaller meteorites. One such shard crashes near Daruma's turtle holder, which is in the process of taking off.
Hachimaru is worried about the meteor, but Daruma is unconcerned: he strategically hid his Holder in an area devoid of people and animals. However, the entire satellite making contact will annihilate the planet. As his Holder flies to meet up with the Samurai in orbit, the people mistake it for a shooting star and begin praying for protection. As the turtle Holder catches up, Hagamichi reaches out to the other Samurai, explaining Daruma's intent to use a star-breaking move and warning them to break off to avoid getting caught in it. As the other Holders fall back, the Samurai are amazed that a legend such as Daruma is aiding them.
Once the Holder stops, Daruma calls Hachimaru to his side. As he prepares to take his student outside, he asks Ann to strengthen Hachimaru through her prayers. Remembering Un's teachings, she promises to pray with all her strength, and Daruma promises to show her Hachimaru's true form. Hachimaru, unaware of what they mean, promises to do his best. Heading topside, he is intimidated by Muun's size, but he then feels a surge of strength build up inside him. Daruma explains that Ann's prayers are the source, then instructs him to expose his Key. Daruma connects their two Keys so Hachimaru can mimic his movements and perform a Samurai technique. While he could give his student a license to use it himself, time is too short for an upload of that size. He then has Hachimaru copy his movements to create his Samurai Soul blade and use Kongo-Yasha Style: Atmos Fangs. While the attack takes form, Daruma explains that his cat body prevents him from using Atmos Fangs with enough power to destroy Muun. Shocked at the idea of blowing a planetoid away, Hachimaru becomes doubtful. Daruma counters that his Samurai body, Hayataro's Handle Bone, Ann's prayers, and his own heroic heart are all he needs to succeed. He then asks if if he wants to save his planet. Thinking of his father, his first friend, and his allies who are trusting him, he regains his nerve. Firing off the Atmos Fangs, the planet's atmosphere warps into a massive sword-shaped blast that turns Muun to dust.
Back planetside, everyone celebrates the fact that they are all safe. Hagamichi stands amazed that he witnessed a legendary star-breaking move at full power. At Akagi Castle, Nanashi thinks to himself that Hachimaru could actually be the next Shooting Star. At Ann's old castle, Yoku watches as the other princesses' opinion of Ann changes. In space, Ann tries to congratulate Hachimaru, but is shocked to see that he has become incredibly skinny, a side effect of using Atmos Fangs. Remembering Daruma's promise from earlier and Hachimaru's belief that he was "a scrawny toothpick," Ann resolves to support him by making plenty of food for him. Daruma assures her that Hachimaru only needs to rest, but tells them to take a moment to memorize the sight of their home. Since they are off to find the other six Keys to open Pandora's Box, they will not return often. At that, he pilots his Holder out into space.