If you want a bit more insight into what my fursona's Deal™ is (though basically just the tip of the iceberg), here you go!

About Katja

Biographical info

Demographic(?) info

• Species: if you want to get into actual taxonomy or ontology here, good luck. Good luck. You can totally call them a catdragon, though, because that's accurate enough.
• But what about the taxonomy: well, they were born as a human, very much ceased to be human, and are now… …check the graph below. They're mostly vaguely in the direction of animal-like, though, I guess. Definitely closer to that than any other kingdoms of terrestrial life.
• Age: my (as in, the person behind the keyboard's) age.
• Pronouns: they/them; she/her also works.

They can easily shapeshift into a different apparent species, adjust their physical indicia of gender, and even adjust their apparent age somewhat. However, they are never smaller than 3,050kg.

Personal history

• Literally just mine, until probably a few months ago (as of the time you're reading this).
• While being transformed from human to Look I Can Assure You They're Ontologically A Mortal I Promise Being Effectively Immortal Doesn't Make Them Not A Mortal is itself enough of a drastic shift, the process also involved… …the details are fuzzy, but whatever it'd take to turn (literally just me) into someone capable of handling that kind of power well.
• They've spent the past few months sorting out the practical aspects of how their new everything fits into their life and the world as a whole, so they have yet to start exercising their power to the fullest.
• Though in RPs taking place in futuristic settings, they might have been, well, this for longer. It kinda depends.

Mechanical details about them worth knowing

I think this chart here should explain everything pretty neatly:

But what does the above chart mean. Seriously.

Below are explanations of elements of the chart that are likely to come up in an RP or art context.

Their soul

Mostly self-explanatory.

Ontological Fuckery Compatibility Layer

Shorthand for the entire set of reality hacks, arcane pseudomagic, and intertwined pacts with incomprehensible forces and entities whose emergent result is a logically ironclad wall of checks and balances against the risks of each individual component, and complex math which bridges the gap between whatever True™ Essence™ there is at Katja's core and normal reality.

Hard light

Terms for Katja's specific kind of hard light in the lingua franca of the people who invented this sort of pseudomagic include ones which gloss to "soulglass" or "Well surely death is actually forever, huh?". (It's a technique that is somewhat of an inversion of how liches work. Rather than using a phylactery to animate a dead body, it allows an otherwised disembodied soul to stay stable in the physical world while channeling its sense of self into actively projecting a live but also holographic physical form.)

It's bright blue, but also inverts the colour and brightness of anything behind it — and has a thickness of 0. It's just a plane in space that matter cannot cross and which distorts energy crossing it. Via some contrived mechanism, it's also the substrate through which the Ontological Fuckery Compatibility Layer syncs with Katja's blue goop.

Blue goop

Exactly what it sounds like. It usually manifests as a suspension of stem cells, nanomachines, and non-allergenic latex. It can change form easily, though — for example, all of Katja's organic and electronic anatomy can become blue goop, vice versa.

In terms of interfacing with other life, once again, it can do anything that cells, nanomachines, or electronic systems can do.

Blue fog

An aerosol of hard light and blue goop. It basically functions as an airborne variation upon blue goop.

An aside that isn't on the chart: instances

In short: Katja doesn't just exist in one place at once — rather, they can manifest an arbitrary quantity of instances. They're all the same person, really, but are temporarily separate, simultaneously existing incarnations of them.

The Katja you see in public is nearly always Katja[0]. You can tell that they're [0] because their hard light is brighter. If some given Katja instance is preoccupied in a longer-term manner such that they cannot, say, participate in society, that is not Katja[0].

Over time, instances will tend to "merge" back into "main" (being whichever is [0] at the time).