Aelyss

Aelyss has a limited inherent ability to shapeshift from their naga form into either a fully snake form or a human form, and has a degree of control over certain finer details of their appearance in their various forms, though some constants and restrictions remain without additional use of cosmetics or magic. Their overall plump or stocky appearance is one of the constants, as are the brassy iris color and some of the blue tones within their mouth. They are unable to change directly between human and snake forms without a return to their natural state, and most adjustments they can make to either of those forms also require a return to their natural form first. Aelyss' base wardrobe is comprised of lengths of cloth which can be adjusted to cover more or less of their body as needed.

If knocked unconscious or sleeping while in snake or human form, there's a significant chance they will revert to their natural form, though preceding circumstances such as focused intent or a sense of danger can influence the chances.

If some tool, spell, etc. is being used to change their appearance, it will interrupt their shapeshifting ability accordingly. Minor changes may simply carry over from form to form, but more significant changes can risk injury if they attempt to change or may entirely lock their form for the duration it's applied. If the change was significant enough, upon its release they will return to their natural form regardless what form they had prior to the change.

Natural Form
Unquestionably serpentine in nature. Aelyss has a muscular snake tail from the waist down with a smooth-scaled humanoid torso and a hairless head that appears strongly reptilian. They usually appear to have a single pair of arms, but are able to produce a secondary, less-developed pair of arms when needed. A layer of healthy fat smooths over powerful, dexterous muscles. Coloration follows a splotch pattern and is predominantly browns with hints of red, olive, and black with a pale cream belly; inside their mouth is a mix of blue and pink. Although capable of making certain pattern adjustments via limited control of gene expression, its rare for them to bother doing this, especially as some expressions can cause various physiological problems. Their body has no external indicators of sex.

Snake
Aelyss is able to retract their arms and morph fully into a giant snake at will. They are able to reduce their size to a point in this form so as to appear more like an actual snake, but still remain a massive jungle snake without something to help beyond their natural ability. As with their natural form, they can adjust their patterning and coloration to a degree, but usually stick to their regular mostly-browns for the same reasons.

Human
When taking on a human form, Aelyss has an easier time changing some details from one instance to another, such as coloration, but they are unable to have their second set of arms. Without a reason to change coloration, though, they will almost always have brown skin and short, dark, curly hair, and they generally whiten their sclera and morph their pupil to appear more circular. Their base androgyny may come out appearing more typically masculine or feminine, or may have notably mixed features. Even in human form, Aelyss is cold-blooded and may be cool to the touch. Their skin may also feel slightly odd and rubbery, especially if they'll be shedding soon.

• Limb Regeneration. If a limb, non-vital length of tail, or some other body parts are lost, they may slowly regenerate over an extended period of time. Regenerated parts will never be as well-formed as the originals, further damage to a still-healing injury can worsen the recovery dramatically, and some injuries may not allow much or any regeneration.
• Infrared Vision*. Able to "see" heat radiation in addition to standard visible light.
• Sectioned Jaw*. Jaw is split into flexible sections; this works in tandem with highly elastic tissues to allow the mouth to open incredibly wide. (Aelyss is typically polite enough to either take smaller-cut "bites" or avoid eating at all in the presence of most "civilized" beings.)
• Extended Glottis*. A second tube in the mouth permits breathing to continue when the throat is blocked.
• Altered Hearing*. Lacking typical ears, Aelyss isn't as sensitive to vibrations in the air and relies more on touch to pick up vibrations than mammals or birds generally do. Their hearing range also sits lower, but still mostly overlaps with that of humans. Aelyss has also been practicing lipreading and understanding other body linguistics to improve communication in particularly noisy environments.
• Limited Facial Expression. The musculature of Aelyss' face is developed for eating more than for communication. Even as they work to better interpret the various expressions of other species, what expressions they are even physically capable of mimicking (a far smaller number when not in human form) still usually take a conscious effort.
• Psuedo-Mesotherm. Though cold-blooded, Aelyss' mass helps to stabilize their temperature and has allowed them to develop a gut biome that generates some additional warmth, allowing them to be a little more resistant to cold than a reptile would typically be. Enough time exposed to extreme enough temperatures can still dramatically change their overall body temperature and can risk wiping out that cultivated biome, and cold can still slow their metabolism and trigger hibernation instincts.
• Shedding. Though infrequent, Aelyss will periodically shed their skin. This typically happens all at once, but poor health, stress, environmental irritants, injuries, and other issues can result in patchy shedding.
• Eye Cap/Brille*. In their natural or full snake forms, Aelyss' eyelids are fused into a hard, transparent eye cap. It helps protect their eyes, but leaves them unable to close their eyes (including blinking) or shed tears in those forms. Harder to notice, they will automatically mimic the structure in human form by use of a thin, soft, nictitating membrane which they keep closed, finding the little extra effort worthwhile to prevent dry eyes from forgetting to blink. The nictitating membrane does very slightly reduce their quality of vision, so there are limited circumstances where they will truly have their eyes open.

* Marked traits are absent from or greatly reduced in human form.

Aelyss is a curious creature in many ways. Their expression is so often unreadable or noticeably forced, they speak softly and little, and their behavior can often seem strange; they also express a clear interest in gathering and protecting knowledge, even regarding themself as a guardian of what they have learned. If there is any "greater purpose" in this, they do not say.

Learning of other species and how to interact with them has enabled the naga to keep expanding yet further on what they learn. Aelyss pays attention to the things valued by various peoples to learn how to tailor their own behavior so as to be more agreeable, even though they always remain somewhat alien wherever they go, especially with their typically steady, precise, and inquisitive demeanor. Learning basic medicine for a wide range of beings has also proven useful.