Melusine Perception

We know melusines perceive the world differently than humans, but how, and why?

First let's get out of the way things that are not general melusine perception

Mamere's paintings

Mamere's work is incomprehensible to most, including the other melusine villagers, who just tell her it's beautiful and have no idea what she's trying to depict.

Canotila's comments

Canotila makes plenty of comments showing she sees the world vastly differently, such as the comment about Paimon being a rainbow balloon and Traveler being a monster that can swallow the world, but she mentions it's unique to her.

Some traits I have little to say about

Having a different sense of smell and taste

Humans get weirded out by melusine food, which is natural considering different diets. Melusines mainly eat tidalga (algae). They're also able to catch fish and some other aquatic creatures without any tools or bait to be fair, the traveler does that.

Finding breacher primuses cute

Melusines love breacher primuses. Glaisti even wants to raise some as pets. This makes sense considering breacher primuses are like cells of Elynas which protect Elynas' body and the melusines. They're also known to guide lost melusines home.

Being able to differentiate types of sand

In the recent event where we had to recover Aino's cake bot, Sedile helped us track the thieves by noting the type of grains of sand that were tracked around. It's probably a useful ability since melusines mainly live around and in water.

Having impressive hearing

If you give Cosanzeana naku weed to plant, she says they make beautiful sounds when vibrating. A lot of marine animals have strong senses of sound, like whales.

This trait is also potentially alluded to in the furnishing description of the larger melusine house, where apparently annoyingly noisy melusines can be shut in as punishment because the house structure amplifies sounds.

Melusines and colors

The way Melusines see colors has been brought up several times.

Mamere gathered good quality blood to make her paints, and was surprised that Paimon couldn't tell the difference between the many shades.

Cosanzeana comments on a flower you give her. She says windwheel asters are golden-red and so bright that staring at them too long burns her eyes a little. Silk flowers are crystal-clear and look like pearls. Sumeru roses have many colors which shift as they moves.

My theory for this is that melusines can see a wider range of the electromagnetic spectrum. Many animals can see some of the ultraviolet or infrared ranges, and some animals like mantis shrimps can even see more wavelengths on both ends. Some plants have patterns that are only visible to UV vision, which could explain what Cosanzeana sees.

Interestingly, humans whose natural lenses have been replaced with artificial ones in cataract surgery can see UV light to some extent, though humans don't have receptors for "true" UV sight.

Maybe related, maybe not?

In Neuvillette's story quest, Kiara mentions that melusines can see bloodstains for a while even if they've already been cleaned up. This could be based on the trope of shining UV light to detect blood that's not normally visible (though in reality that requires adding chemicals). But it might actually be related to other properties of the blood itself. In the painting quest, Mamere says common paints "won't be able to portray the warmth that (Traveler) emanates or Paimon's shininess", unlike the ore that turns out to be blood. That said, Elynas' blood is pretty special, and Mamere also says the "shortcuts" (portals in Elynas' body) are "safe" and "warm", while Paimon describes them as "ominous".

Melusines and THE SUN

When Sluasi is trying to make paints "as shiny as gems and as bright as the sun", she asks us to bring items that are closest in color to the sun. We bring her something yellow, but she says she feels the sun is lighter. We bring her something white, but she says she feels this is the opposite of the color of the sun. Finally, we bring her something black, and she goes off to make paint.

The quest is called "The Three Primary Colors of the Solar Corona".

(Side note, regarding the "Three Primary Colors" part of the name, Sluasi doesn't recognize those colors as anything, but it might be referencing something else in Genshin lore. I thought of the alchemical stages which are black, white, red, and yellow, but red isn't included here.)

In book lore (Perinheri), we've heard of a "dark sun" in Khaenri'ah, which seems to refer to the Eclipse Dynasty. Honestly, I used to think Eclipse was referring to a lunar eclipse since this dynasty displaced the Crimson Moon Dynasty, but after learning the name "dark sun", it's clear it's a solar eclipse. This would fit with the "Solar Corona".

There's very little about the sun in Genshin, but the (conflicting) legends of the Solar Chariot suggest the Sun exists in a similar way to the Moons. We also know there are 2 major opposing realms, the Light Realm and Void Realm, and Void is associated with the Abyss. It's possible that the sun being blocked enables abyssal power to exist, like how in real life we can look at the sun when it's fully blocked. Notably, melusines are related to the abyss to some extent, since they're born from Elynas who is heavily implied to be an abyssal creature.

If you think about a total solar eclipse, Sluasi describing the sun as bright but also best represented by the color black actually makes sense.

(source)

Additionally, if Sluasi receives a nilotpala lotus, she wonders why it was named for the moon if it's supposed to be close in color to the sun, and Paimon asks if the moon and sun are so different in color. If melusines can see the real sun and moon, it would make sense that Sluasi finds them to be very different colors.