(Painting by OktoberBeef, https://www.furaffinity.net/user/oktoberbeef )

From the Scrolls of Dee, found in her personal library under the Tower of the Sphinx. Extracts from Dee's journals, most dated to Dee's third year of study there:

... Esc, my keytool, was built with a number of parts that help it more or less emulate its mythical template. It might not be able to change its shape, but beyond its computing power, software and libraries, it has phased-array laser dioes over much of its surface which serve as, among other things, chemical analyzers; some tiny radars, including in the terahertz range; and a collection of sensors on its underside that measure various biodata. All of which have given me some insight into the less-visible parts of my anatomy. (It also has everything from solar cells to a laser-mediated remote electroshock emitter. And most of its processing power is taken up by something that's a descendent of AlphaGo Zero and GPT-3, which isn't a person, but comes close enough to acting like one to serve as a secretary, therapist, and general factotum.) ...

... Going from the top down and outside in, I have a goat's horns; a bird's head, shaped mostly like an oversized magpie's; a pair of wings which are entirely functional in the local centrifugal pseudo-gravity; a pair of arms much like a bird's legs; a goat's udder; a tail shaped like a snake, which is as much a part of me as my more usually-placed head; and a pair of digitigrade legs tipped with cloven hooves. My fur, feathers, and scales range in shading from cloud white through desert-sand tan to dark black, with a certain amount of pink skin showing through here and there. ...

... 'Age' is a tricky concept to apply to me. I remember living for four decades and change, I have no idea how long ago my first life was but it could be anywhere from thousands to millions of years, I think my body started to be assembled four months before I woke up, and developmentally it seems to be Tanner Stage Five which in a human is usually anything over sixteen years old. ...

... My eyes have nictitating membranes and double eyelashes that serve to protect from sand and dust. I've also got a tapetum, a reflective layer behind my retina, which helps me see in the dark. ...

.. My skin cells have been laced with a few sorts of flexible carbon fibres; enough to help with scrapes and small cuts, not enough to prevent major damage. My bones, on the other hand, are much more thoroughly reinforced, particularly my skull. Someone could hold a firearm to my head, and if it were anything short of a large rifle with armor-piercing ammunition, I'd end up with nothing worse than a flesh wound and a headache. Not an experience I want to repeat.

As for what's inside my skull... well, it's not exactly a standard brain. One of the words that can describe me is "holobiont"; another is "chimera". Instead of neurons and glial cells, the stuff I use to think is based on an organism called a 'glass sponge'. As best as I can tell, after my first life, people came up with ways to use living cells for classical computing, and it was easier to stuff a near-independent organism into my new head and load a software copy of my mindstate into it, instead of trying to arrange zillions' of neurons' axons to match how my brain was originally wired up. ... I haven't figured out just how 'near-independent' the sponge actually is, but given what I've been able to read up on glass sponges, it's not outside the realm of possibility that if someone scooped it out of my head and put it in an aquarium, or in the ocean, it'd survive just fine for the next ten thousand years. Which would certainly be rather awkward for me. ...

... I don't really understand the details, but my lungs, airsacs, and other breathing tubes don't really match any anatomy in Esc's libraries, and somehow extract all the water I need from the air save in the absolute dryest deserts. Even when I'm at my sweatiest, as long as the humidity is at least seven percent, I don't need to take a single sip. Part of that is possible because the rest of my biology has been tuned for desert life, recycling as much as possible; for instance, my urine is so concentrated that it evaporates into crystals almost as soon as I pass it. My lungs are a little less efficient at extracting oxygen from the air I breathe, but some other adjustments to my biochemistry have helped compensate for that; my liver and muscles hold a half-dozen times as much myoglobin as an ordinary mammal. I can hold my breath for, oh, half an hour without even really trying. ...

... I've learned I'm quite capable of digesting cellulose, though I still need to get at least around a third of my calories from other sources. Given the environment I first found myself in, I spent some weeks as a full carnivore. ...

... Without getting into uncouth detail, I've learned that I'm both oviparous and potentially parthenogenetic. ...

... My hips, shoulders, and the rest allow me to be as comfortable walking on four limbs as on two. Which I've found handy more than once after I've pulled a back muscle; which happens annoyingly often. I suppose some tradeoffs had to be made when designing all the muscles and ligaments for a pair of functional wings on my torso; and if it's the price I have to pay to be able to fly under my own power, it's certainly more than worth it.