Science fiction stories usually focus on how situations could be different in the future when we are more technologically advanced; due to either our own achievements or having met with other civilisations whom we have learnt from.
SciFi — Subcategories
An extraterrestrial life-form, possibly intelligent and/or extremely threatening. Aliens come in all shapes and sizes: They may be ethereal beings as in Final Fantasy: The Spirits Within, quite humanoid as most of the female space-faring cast in Tenchi Muyou! GXP, or totally incomprehensible as in Gantz. Not the sky is the limit, but the anime author's imagination.
Humanoids are aliens, intelligent beings who do not originate from Earth, but have a striking similarity to humans or at least show the basic body layout, i.e. two arms and legs, head with two eyes and ears, one nose and mouth. Though the latter — head-related features — may vary. As DearS shows some aliens actually exhibit super-human beauty, or as in the case of Onegai Teacher they are genetically compatible to humans for some strange reason.
Parasites are aliens, usually intelligent life-forms that feed off other beings in some way. For shock value, and to avoid having to draw aliens all the time in anime, the prey of parasites is preferably human in nature: Parasites may see humans as food, as a puppet for mind control, or simply as a temporary body host. In every case the human is the victim of the "merging" — not to be confused with the more "amicable" symbiosis.
- Examples: Tetsuwan Birdy Decode
The enhancement of humans can take various forms: It can be something comparatively non-intrusive as a power-up drug, a form of machine implantation or cyberization (SAC Solid State Society), or outright — possibly atrocious — genetic manipulation (Ao no 6-gou). Plot-wise enhanced protagonists in anime usually have to pay a price for their enhancements, be it physical or mental.
Cyborgs are humans, who have been taken over in part or in whole by cybernetic or electrical/mechanical devices, which either control them or which they retain control of. The term comes from "cybernetic organism", which literally means an organism that contains both mechanical and organic components.
Story-wise Genetic Modification is usually centred on humans, probably the most subtle and creepy way of messing with mankind. Playing with the fear of the unknown, genetically altered humans are technically a new species, that may not only surpass but actually replace unaltered humans. The level of modification will vary from subtle changes in "look" (e.g. super-human beauty), to mental enhancements (PSI powers), to more or less atrocious adaptations to extreme environments (breath under water, radiation resistance). Note that changes in Aliens would be difficult to pinpoint, after all they are alien.
- Examples: Akira (PSI powers), Appleseed Saga Ex Machina (species Bioroids), Ao no 6-gou (environmental adaptation)
Mecha in Japanese basically means mechanical things; everything from an electric whisk or a car to a spaceship or a robot. Here however we limit it to the more exotic things usually referred to as mecha anime: robots, whether controlled by a human or not, and their ilk. We further specify what kind of "mecha" you're likely to find in an anime with this category in the subcategories.
Androids are robots created to look like humans. A very famous example is Data from Star Trek, but they need not be as human-like as him.
Piloted Robots are, as the name suggests, robots that cannot control themselves; they need to be steered from somewhere, this can be from a human sitting inside or a remote controlled option.
Power Suits are similar to Piloted Robots which are controlled from inside the robot except that Power Suits tend to be more directly tied to how the character moves and they are usually not as big as Piloted Robots can be.
Any protagonist of repute in a SciFi setting requires a side-kick (also for comic relief at times). Whereas other anime will have a cute animal side-kick, in SciFi the corresponding equivalent is the Robot Helper. A mechanized AI (artificial intelligence) that assists the character in tricky situations.
Transforming Robots includes mecha that change shape from their original either to facilitate better/different functionality or as camouflage.
Space Travel usually refers going to space or travelling there with or without a spacecraft. There are different forms of space travel like Interplanetary travel, Interstellar travel or Intergalactic travel. Since it isn't possible to travel faster than light, most anime series involve some sort "sub-space travel mechanism" as a way to travel faster than light.
In time travel anime characters are transported through time either figuratively or literally to find themselves either in the past or the future.