Ok, Theory
Ok so in the webcomic Aurora, the “main” character Kendal is an entirely new uncategoriseable entity, a god’s incarnation that survived the god leaving it and developed its own mind and personality.
Now the god that this happens to is the hero god of the city Vash and, like the Ancient Greek Eros or Nike is named after his domain. So what we know about Vash is that he cut his teeth in this god business by defending his city from and defeating the storm god Tynan, the way he does this is explained here with an in universe telling of the story. What we know is that an alien metal and jewel was worked into an incarnation of Vash at a thematically appropriate moment and became an extremely effective power up, enabling Vash to defeat the hitherto undefeated Tynan.
Now how this works in the world built magic system of Aurora is really interesting. So in Aurora it appears they're are two (or eight depending on how you count it) fundamental substances of magic, the elements and soul energy, now we know where elemental magic comes from as a central piece of lore in the main storyline so far has been about the ancient war between the elementals and a Void Dragon and how the elementals died defeating this Void Dragon and their bodies meshed together supplying the materials as the world, but the elements still count, and can be persuaded to act, as one body essentially unique to the other elements and so because they belonged to a living entity with a soul can exist in two states, the material element and a sort of potential/soul element held in other materials or channeled by mages to enact elemental effects.
Now soul energy is something very different and despite the excessive amount of time I've spent explaining the elements, is what we’re focusing on here. Soul energy is what living things are “made of” being literally the material of souls, now I could be wrong but from I can figure out everything alive contains and in someway uses soul energy, and soul energy has a connection with other soul constructs allowing for an in any capacity uniform group of living things to develop a larger social soul that becomes a god. Vash for instance is a city of people and so through the interaction of their soul energy, construction of early incarnations, and people assigning these incarnations personality or motivations became the hero god the city imagined, as the god itself is made up of the whole cities population who once saw incarnation interpreted them a certain way and influenced some of their aspect. Basically, because the god is their domain how they are viewed by the creatures in their domain effects their personality and most comfortable form.
So what does this really have to do with Kendal. Well if Vash’s sword was constructed from an alien metal, a solid substance, which issomething almost impossible to make without an elemental, after Vash worked his soul energy into like soul shaper monks do with human prosthetics, which would more than likely work some of this starmetal soul energy into his own soul lattice. Then its likely that Kendal’s soul is made of what little of soul star metal was in the solid material of the meteor. And it’s not just background lore magic systems backing this up.
In the series of pages telling the mythical story of Vash’s Sword we find out that it’s being told through the framing device of the smith god who forged it, to a similar style god to Vash of the Fire influenced race of Ignans. Now while why they're talking and what this incredibly effective smith who uses the arcs and emotional journeys of the wielders of his weapons in his smithing process is doing with a god of fire and fire people directly related to one of our adventuring party is incredibly plot important and personally intriguing, there is something else I wanted to focus on here.
In these panels Tahraim appears to be talking about Dainix, a character Kendal is currently imprisoned with and who are jelling suspiciously well. Now we can see that Tahraim is using his Xanatos gambit forging technique of social engineering to forge out a weapon and fighter for Caliban (probably to fight the fire demon from Dainix’s backstory (who is probably another elemental emissary for Fire (like two other characters currently being heavily associated star metal soul Kendall (I see you Red, with each subsequent layer of brackets I get closer to the truth, witness as my bracketry grows)))) and describing some of the forging fires he’s using fo this weapon (who is probably Dainix, if not definitely)calls one of them “the divine blade”, referring to Vash’s starmetal sword currently held by Kendal, but the blade its self is isnt world shaking, its been around for millennia and everyone is very familiar with its power and prowess as a sword because Vash is an incredibly well known god. But that’s only as a sword, and we know Kendal is world shaking after his discussion with Ilia here where he is told explicitly that the gods fear what he represents but respect the fact that he is an incredibly powerful being with all the strength and ability of a godly incarnation but with no responsibilities of upholding a domain or the limits of staying within they’re domains range. And so the theoretical soul that is Kendal in this incarnation must be made of whatever remainder of star metal soul is left from the solid star metal in the sword. That had been given the shape and properties of a human/incarnation soul by being weaved into and by Vash and then had the Vash soul ripped apart from they’re shared incarnation leaving the star metal soul to have to develop as its own being in this body
And if all you wanted is proof of this theory you can honestly stop reading here. So far this is dense and a lot and I wanna run through some stuff with this head cannon to nerd out. So if you don't wanna have to read anymore, my argument for this theory is basically through
Kendal being the star metal soul can provide a reason for, guess plot dent instead of plot hole? when Vash takes Kendal to where he is being held by the Collector. The reason this could be a plot dent is that one of the working theories for why Kendal exists can be found in the Sentinels. Essentially building sized stone statues animated by a god semi incarnating in them, its hard to explain so if your interested read here (Also read the comic, it’s really, really good. Like really good. If you get into the extra lore on the website and then scroll through Red’s Aurora Tumblr answers you get to appreciate how truly spectacular her worldbuilding and magic systems are. I mean clearly they’re cohesive and well thought out enough that just off of the magic system you could make a (if I don't say so myself) well reasoned prediction for a major character reveal.) the theory being that because these Sentinels can develop these echoes after being un-possessed by a god over time, the unique way Vash was taken out of his incarnation without dis-corporating it that the body developed a similar echo and is now ambient soul energy drawn into the empty body. However, this wouldn't make sense with Vash taking Kendal to the Collector’s hideaway in his sleep, as if Kendal is made of ambient soul energy he has no actual connection with Vash’s soul and so Vash shouldn't be able to bring him to the crystal he is being held in. But, if Kendal is in fact the star metal soul then he would still have that connection with Vash, as they are the same soul but different parts made of different materials, and so ca operate separately whilst still being so intricately connected.
On one final note, there is one character that already seems to know all this, Tahraim. That Kendal in everyway is the weapon he forged, that they're is a capacity for new elements and therefore different soul energies, that Erin has been possessed by the Void Dragon, and that the Collector has revived life, who has taken Alinua as an emissary, and is using this information not for his own divine or dastardly machinations but on commission. Which is A) a potential threat if Tahraim turns out to be a tad more amoral than he first appears, working as effectively for the next customer instead of esoterically guiding events for the cause of good and B) show cases an incredible mesh of world building and character work with gods being influenced by how their perceived and a god perceived and heralded as an unachievably proficient smith knowing more than any other character or entity we’ve ever seen before and doing exactly what is necessary to forge his commissioned weapons into the most powerful and effective instruments they can be almost only because of how in the magic system some gods are made from ideals and interpretations instead of groups of living things and actually fits the way they are most commonly perceived