In the beginning, Saturno is nothing but a blob, but by eating other blobs and small demons Saturno grows, and starts becoming bigger and stronger, taking in the characteristics of the demons eaten.
But it's not enough.
The Demon World is actually a giant, planet-sized demon that can create offspring in the shape of the little blobs. The only way to get bigger is to eat other demons, for if anyone tries to eat from the Mother Land, it bites back.
Nobody's safe. Saturno only wants to be safe and live. What's the next obvious step?
Become the Mother Land, so that nobody is bigger than Saturno and thus nobody can eat him.
This is only the first arc. The second involves a portal that leads Saturno to another world, where he learns about giants who kill but don't eat their kills.
The third arc is of how Saturno becomes part of a "club" that aims to be like those strange beings from the other world.
Word of God: "I hope I can finish by 2012"
A mirror can be found here.
Provides examples of:
- Ambiguous Gender: The title character until well into the third arc. Then it chooses to be a he
- Bishounen Line: The main characters seek to cross it. It gives them a bit of an advantage once they get massive enough to need to compact their forms to maintain human shape, leading the other demons who think Bigger Is Better to underestimate them.
- Body Horror: A given, considering that every time a demon eats another demon, their body mutates taking in characteristics of the eaten demon. Seems like the more powerful a demon is the more control there is on these changes however.
- Chekhov's Gunman: The white giant. Also known as the leader of the human club, Alpha
- Collector of the Strange: Considering demons don't have much time to worry about anything other than eating and not being eaten, the fact that the human club exists, and the fact that it has actual human things definitely brands them for this trope.
- Covert Pervert: Seems like Nike was particularly interested in Saturno's gender selection...
- Crapsack World: It's a dog-eat-dog world taken Up to Eleven.
- Death World: The only possible reason why a human being might survive in this world is that they are too toxic to be eaten. But there are questions about the atmosphere, and every life form is carnivorous, and probably doesn't realize that humans are not food.
- The Faceless: Nike's massive hoodie conceals an enormous toothed maw that's seems to be his only feature..
- Genius Loci: The world where Saturno is.
- I'm a Humanitarian / You Are Who You Eat: One of the main "perks" of being a demon. Only works with demons, as proven by the Man Eater.
- Light Is Not Good: the path to The wasteland which actually is the human world is a big hole of light in the pitch-black demon world.
- Mood Whiplash: Compare the harsh start with extreme dog-eat-dog world with the later arcs. The art shift is also meant to be part of it.
- Naked People Are Funny: Played with. Demons who want to be like humans don't get things exactly right. One doesn't have skin, showing only muscle anatomy of a male, while the other doesn't seem to have a head, but wanders around in an anatomically accurate body... of a female.
- Pintsized Powerhouse: Compared to the bigger demons, Nike is relatively tiny. And none of them can stand a chance against him.
- Room Full of Crazy: Saturno attempts to learn reading by copying every written symbol from every language on the wall of his room.
- Sand Worm: Some demons are seen in the story to take this shape.
- Shapeshifting: A basic part of demon behaviour.
- Split Personality: If demons don't kill their food before eating them, they absorb their minds, thus becoming a body with two (or even more!) minds.
- It's later revealed that once demons reach a certain size, if they've eaten their food without killing it the whole time, they start to experience Sanity Slippage from the huge number of personalities inside of them, and eventually completely lose any sentience they had, and start madly engaging in self cannibalism, multiple mouths attacking each other, without realizing that they're all part of the same being.
- Tempting Fate: On page 494, Saturno gives us the line "I'm a shapeshifter! I'll get the power back!"
- Training from Hell: From the hands of Vinci to Saturno.