Years ago, I wrote a post about character chemistry archetypes in which I defined the five most prominent character relationship archetypes I could think of. I thought of another one while watching the recently released film Big Hero 6 (which was a good movie, by the way):
The Human and the Inhuman / Less-human
Examples: Baymax and Hiro, Toothless and Hiccup, Stitch and Lilo, ET and Elliott, Terminator 2 and John Connor, The Iron Giant and the kid in that movie, Groot and Peter Quill & company, Ludo and Sarah in Labyrinth
In this relationship, one character is clearly human (or at least more human-like), while the other is less human. The less-human character might be an animal, a robot, an alien, or even a human with, for example, a mental disorder that makes him more difficult to relate to. These characters usually communicate differently; they may have limited vocabularies or be completely mute. They are often closer to nature than the human character; they may have a special relationship with plants or animals (or even rocks in Ludo’s case). They may have a healer’s touch, in the case of E.T. and Baymax. Often the human character will try to teach the corresponding less-human character how to be more human, sometimes with humorous results. On the other hand, the less-human character will often teach the human character something important with his unrelenting loyalty, courage, persistence, and willingness to sacrifice himself for others. In this way, the less-human character, while he may be difficult to relate to and simple and ignorant in many regards, is also closer to the divine. In fact, in stories in which these relationships are at the center of the plot, it’s the less-human character who often gets the “martyr beat” instead of the main character. In Big Hero 6, Terminator 2, The Iron Giant, E.T., and even Guardians of the Galaxy, these less-human characters sacrifice themselves to save the main character (sometimes resurrecting, sometimes not). How to Train Your Dragon is interesting because Toothless and Hiccup actually share the martyr beat.
These human / less-human character relationships can be quite powerful when well-written. I think the reason they can work so well is that the less-human character represents something already inside the main character that the main character must learn to reconnect with. That is, the less-human characters leads the human character to a needed self-discovery.