The Battle Star is the last remaining bastion of humanity, besieged by alien forces. Raiders and marauders take what they wish, with the once-mighty empire of Industria reduced to a single city.
Astro doesn't care about any of that, however. He's a street urchin who takes in any orphan he finds, and works to earn enough money so they can all eat.
One day, a boy who looks exactly like Astro pops up. He is Barragenote , Prince of Industria, but he is tired of his role and his father. So he gives Astro the Org, the Ancestral Weapon of the royal family, and runs off to live a life free of responsibility. He is immediately shot.
Astro ends up dragged to the royal palace, where everyone realizes quite quickly that he is not the rude and ill-mannered prince. But the Org reacts to him, so he is charged with freeing the Battle Star from petty tyranny by traveling the land defeating anyone oppressing the weak. The captain of the royal guard, Tiamat, is sent with him to ensure his safety.
The second mainstream manga of mangaka, Kohei Horikoshi. Started and ended in 2012 with 16 chapters due to low readership. It was picked up by Viz for an American release however and covers at least two volumes.
This series provides examples of:
- Action Girl: Tiko. Her very first appearance in the manga has her blow up Astro and Tiamat's carriage with a rocket launcher.
- Allergic to Love: Tiamat has...problems with women.
- And the Adventure Continues: Due to the manga being Cut Short.
- Animated Actors: In the "Party from Hell" mini-arc, all of the characters are portrayed as actors who've just finished filming the manga, as a film. Interestingly, a lot of the actors are apparantly Playing Against Type for the manga: for example, Astro is really an emotionless prodigy actor, Tiamat is a heartthrob, Tiko is a timid rookie, and Jino is a pin-up model.
- Broken Pedestal: Mr. Black to Astro
- Cut Short: Couldn't gain enough readership in Jump and was ultimately cancelled. The final chapter sees Astro battling against the man who inspired him to do right.
- Dead Star Walking: The entire manga is named after a character who doesn't even last five pages before he's killed. Then again, he's not the real Barrage, anyway...
- Death by Irony: Barrage is unwittingly shot dead by the very royal guards that were sent to retrieve him.
- Fallen Hero: Black
- Identical Stranger: Astro and Barrage look exactly alike. In chapter 14, it is revealed that Astro was the real prince, spirited away as an infant to be raised away from the corruption of the royal court and replaced with a dark matter duplicate.
- Imagination-Based Superpower: Dark energy. At its most basic, it can be used to enhance muscles, but more skilled users can form solid constructs.
- In the Blood: The Org turns out not to be reacting to Astro's pure heart and courage, but to the fact that he's the real prince all along.
- Jerkass/Asshole Victim: Barrage is quickly characterized as one before his death, and it's only further cemented as the opening chapter goes on.
- Morph Weapon: The Org is a bracelet in its base form, which then transforms into a spear. Turns out it can take other forms as well, though they're having trouble figuring out how to trigger this.
- Only the Chosen May Wield: The Org responds to courage and conviction, transforming into a weapon when its master faces someone they consider an enemy. Turns out that it's the royal blood that counts.
- Parental Substitute: Astro has a whole gaggle of orphans he considers his family. He only agrees to play the part of the prince on the condition that they are taken care of.
- Phlebotinum-Handling Requirements: Astro's weapon is described as working only for those who have the qualifications. Initially, it's assumed to be his bravery and pure-heartedness, but it turns out that it's actually royal blood, which Astro secretly possesses.
- Reasonable Authority Figure: The king of Industria just wants his people to be safe. Unfortunately, he is old and weak, so he can no longer use the Org.
- Royals Who Actually Do Something: The king used to be this, but now he is too old. Astro is the fake version until recent chapters reveal he is the true prince of the planet.
- Space Whale: Mira, Tiko's companion and means of transportation, is one. She's sentient, able to talk, can travel on land, and is actually quite polite.
- Switched at Birth: Astro and Barrage. Astro is the true prince while Barrage is just a being formed from dark energy.
- Thou Shalt Not Kill: Either this is how Astro thinks, or the Org just won't let him do it.
- Ungrateful Bastard: Astro's boss in the first chapter. Astro saves him from one of the alien royalty who was going to kill him for accidentally bumping into his stead. The boss repays Astro by firing him, stating that the alien could come back for retribution. The boss was shown to be a bit of a Jerkass anyway, docking Astro's pay for complaining about the heavy boxes he has trouble carrying for him.
- What Measure Is a Non-Human?: It's not specifically brought up, but the way the manga takes this is... complicated. While Astro and the Industrian army have absolutely no problems with specifically tracking down and apprehending aliens, this could also be attributed to most of the aliens shown being genuinely evil instead of just plain Fantastic Racism. An especially glaring example would be Gordon, the lizard nobleman from the first chapter, who's a jerk, looks down on the poor, threatens the King, and nearly kills Astro. Meanwhile Suntara, one of Astro's kids, looks to be the exact same species as Gordon but he's accepted into the royal palace just as eagerly as everyone else, without so much as a word. In the end, it seems that nice non-humans have no problems living whatsoever, but the majority of them are just trouble.