While not a character in the show, a teaser at the end of episode 12 of Interviews with Monster Girls introduces one last Demi-chan. Unlike the previous monster girls, which are based on monsters out of various mythologies, our unnamed invisible girl is based on a novel, specifically the H.G. Wells novel, The Invisible Man, first published in 1897. While the novel might have had some similar themes to Plato’s parable The Ring of Gyges, it is an all original modern-day monster. In Plato’s story, a shepard gains a ring that allows him to become invisible, while in The Invisible Man, the invisibility is gained through science. The H.G. Wells novel is interesting in that the main focus of the story is the main character’s descent into madness due to his inability to interact with the world around him.
The invisible girl from Interviews with Monster Girls and Toru Hagakure from My Hero Academia, also invisible, do not seem to suffer from this problem. Neither one of them seems to have a problem interacting with others and appears to be rather well-adjusted. The most logical explanation for this is that they both grew up with the condition and learned to live with it, while the Invisible Man has to grapple with being made invisible as an adult. In fact, the only physiological quirk the girls have is dealing with nudity as each one is embarrassed by removing her clothes, when no one could see anything anyway. The short explanation for this is that society would expect people disrobing in front of others to be embarrassed, so the girls are trying to behave like society would expect them to, even when the other characters point out how much it doesn’t make sense. Either way you came here for the science and not the psychology.
I’ve talked about eyesight several times in this blog, so it should be no big surprise if you have already figured out where I am going on this one. For a human to see anything and the eyes to work, light has to pass through the eye and make contact with the retina for a person to see.
When no light hits the retina we can’t see anything, which is why we can’t see in pitch black conditions, when there is no light, or if the eye is covered by a patch. So basically, light needs to hit the retina for the invisible girl to see anything, and she has one small problem. She just so happens to be completely invisible.
The light passes completely through the invisible girl and Toru, which means that the retina cannot absorb light, making them both completely blind. While this is a setback, it is not an impossible situation as their other senses will function just fine.
I discussed this briefly in a previous post on the quirks of My Hero Academia, but I will try to expand on things a bit.
There are no organisms living or dead that have ever had complete invisibility, but there are some that have had some degree of partial invisibility. Many of them are aquatic, but there are some that live on land, and many of them are smaller in size.
There are three main issues when it comes to making an object, let alone a living organism, invisible:
1- low absorption of light by the body tissues
2- a lack of dispersion of light as it passes through the body
3- minimal reflection of light when it hits the body
These three issues are important and they all work great when the object or organism is small and thin, allowing the light to pass completely through the object as if it were glass. Sadly, the human body is neither small nor thin, so a different approach is needed. Now I know that I said that there is no way for Toru to be invisible in my discussion of the quirks of My Hero Academia, but after some advice and more research I have found a possible method for the invisible girls to exist.
It was brought to my attention at Otakon 2017 that chameleons use tiny crystals that reflect light differently based on their shape and how far apart they are. The use of light reflecting crystals instead of pigments changes how chameleons change color and it is still being explored.
It also opens up a new avenue of discussion and gives a potential explanation for our invisible girls. To be invisible the light has to travel through the girls as if they weren’t even there. Sadly, the rules of physics make this impossible, but there is still a way to make the girls appear invisible. You have to take the light and move it around the person or object so that the observer can see the light coming from behind the person in front of them. Science can do this with cameras and screens and it is being explored as a means of camouflage.
Now let’s go back to the chameleon for a moment and its small crystals, which can reflect light like a mirror. The mirrors can reflect light from behind the object to the observer in front of it, making the object invisible to the observer.
The trick of course is being able to detect the incoming light and reflect it in just the right manner, which would be impossible given how the invisible girl is blind. However, if she could detect the incoming light, tiny crystals in her skin could reflect the light around her body, granting her invisibility. The chameleon can adjust the crystals in its skin, so the invisible girl would also have the ability to do that as well, but this adjustment takes time, and the faster she moves the more likely that the crystals wouldn’t be able to keep up. This means that in combat Toru’s and the invisible girl’s invisibility would not be complete.
If I had to rate Toru and the invisible girl, I would have to say that they are busted, because there are just too many unknowns, and some of the explanations are a bit of a stretch.
FYI- the way that Tetsuo visualizes the face of the invisible monster girl is the reverse of what a blind person would do to see someone’s face. Also if Toru can bend the light around her to make herself invisible, she could also potentially focus the light moving around her into a laser.