coalmine

because im so fucking tired of slander lmao, feel free to only read the image notes, draw ur own conclusions and add on to mine, bc this one is a doozy

Been making small observations for a while, and now that we know what he used to look like it's as good of a time as ever, so here goes nothing.

Newborn narwhal

Ajax's color scheme used to be mostly blue (early indicator of Hydro) with earth-y tones present, it's a very grounded look that ties him to his previous life and lost childhood. His undershirt splits in a lambda shape. He even used to sport a sort of scarf covering his neck in a direction similar to later looks. Can't help but note the two belts near his neck, like his self was restrained in a way. The DNA shape's connection to Sourcewater Droplets and Primordial Sea hint at his future as well as his current state of being: the origin of his problems, the source, if you will.

Wound

Now, the bulk of this analysis is dedicated to Tartaglia's base design, as it is one of the best showcases of a large amount of info hidden in a relatively simple look. Color change is a sign he has strayed away from his old self and his fate. The blue hues are completely gone, aside from his ever dead fish eyes, the last drops of his old values. Instead he got a bunch of reds, even the grays are in the red-ish register. Thus begins the cascade of bodily comparisons.

The scarf kept its basic shape from before, and is now distictly blood-red. It's flowing from a jewelry piece located where the two belts used to be. It's an open wound, that oozes with Hydro energy when he uses his vision. Light blue a symbol of purity, as seen in pure vs tainted waters of Fontaine's Phantasms, and Tartaglia is losing it rapidly.

His jacket has a white "belly" (and back), a common trait for cetaceans. It unravels in the same lambda shape along with the deep red shirt (more blood or muscle tissue), starting at the aforementioned wound. The gray streaks on pants are outlines of leg bones with 4-pointed star motif that shows up all over his (and a few other characters' (like Traveler)) outfit, especially in jewelry, like the two buttons near his collar. (The significance of this symbol has been already mentioned by other analysts, so I'd rather not to get into it, sorry)

I read the position of his mask as a head wound, not just because it's red, but because of the red jewel in his earring, it goes along with blood drop theme seen in the other two similar gems and their respective locations. The armor plates on his hips wrap around, forming a pelvic-like structure that connects with chains to a dark streak on the back of his jacket forming the base of spine and followed upwards by vertebra-like jewelry. A chain connects it to the chest wound in a rib-like direction. The scarf is held in place by a shoulder blade piece (whales have shoulder blades too).

So we got a fatui soldier uniform that manages to also depict a wounded whale-like creature. I say "like" because pelvis and femur are decidedly humanoid.

Decay

It proved to be fatal. The purple of electro delusion also extends to dark grays of the uniform, creating a rotten flesh look, enhanced by the new hue of red in his scarf and a pink-ish streak on it. Incidentally, purple in Genshin Impact is frequently used to signify curse and contamination, specifically god remains, as seen on Yashiori Island and in Sumeru desert near Consecrated beasts. The shirt is showing from under it all like bones.

Childe's left eye is covered with a red patch on the same side as the earring, could be seen as it getting covered in blood or as him losing that eye altogether. The structure of his mask has a basic shape of a fantastical narwhal, it is foreshortened from front view, as if the whale is approaching.

Lastly, I found the delusion symbol on the back of Tartaglia's vision while messing around in photo mode, as seen on the screenshot. I highly doubt it is lore, likely just an asset hidden on the model so it can be flipped while animating the Childe boss. This could be supported by looking at the back of Arlecchino's vision, which I haven't done. Dunno if this was discovered before, just wanted to share this find while I have the chance.

Remains

Foul Legacy, of course, resembles Abyss Heralds in structure, so I'd like to focus on what remains of Childe. Abyssal armor is now even more like human skeleton. The mask kept its basic structure and is also a callback to Teucer's favorite Mister Cyclops. The iconic red collar doesn't even connect to a shirt anymore but instead flows into a white scarf, then into tainted purple and finally to a sea of stars. It's a messy amalgamation of his human form that has ascended to the sky, or into the Abyss, take your pick.

I find it particularly interesting how his vision is now where the lethal wound used to be. Did it stop the bleeding? Or did is cause the wound in the first place?

Foul Legacy's color scheme included the blue hues back, closing the cycle. As for the final color I'd like to point out, its the hair. The ginger that never meshed with any other color, yet was preserved in every evolution stage as a reminder of Childe's identity. As a reminder, that all of these looks and everything he ever did - is still him.