Personality

Speaking trait: Hissssesssss liiiikkkkeee thhhheee whhhiiinnnnnddddhhhhh... Incapable of true speech, Moony on the fly created thin ice crevices within its shadowy body, and simultaneously creates wind that blows through these crevices, imitating speech as best as it can. Therefore it's hardly ever capable of anything louder than a hissy whisper, although if it wanted, it could create some unbearable whistling.

Character traits: Literally a shadow, seems to only care about Laira, although certain triggers will make Estra inside respond more, shadow personality makes it loyal and doting only over Laira all the time, and has it feel lost without her, Estra personality gives it the cynical, sarcastic approach to people, which may come off almost as if Moony was jealous over anyone making friends with Laira, which may be true in some cases depending on how much they remind Estra of people she used to know. Has a moth-like relationship with light - likes being close to it to be visible, but too close starts melting its ice and weakening its figure.

Specific traits: Looks like a 2D Laira silhouette from all angles even though it has a 3D structure, the stronger the light around it is, the more transparent Moony appears, face is two eyeholes and a mouthhole, both exagerated for better expressions, the 3D structure is often covered in thin frost and ice, and Moony is always surrounded by a chilly aura and icy wind beaming from it. When around Laira, its legs will often dissapate into a stream that connects it to Laira's feet, but it's capable of leaving Laira's side entirely for an unknown yet time.

Likes:

Colours: Red, golden, pink

Food: None

Season: Winter

Animal: Huskies

Remaining: Laira, her music, playing instruments (even if it's bad at them), winter sun (not strong enough to hurt, but allows it to exist), lamps with covers

Dislikes:

Colours: Orange

Food: None

Season: Summer

Remaining: People harming Laira in any way, the Star family, her labmates, strong sun, open fire, being away from Laira, harming Laira

Combat/Abilities

Skills: Immense control over shadows and cold (+ possible other associations made with winter, like the wind), shapeshifting, intangibility

Accessories (*optional): *Laira, icy aura

Strengths: 

can't be killed or harmed by normal means
can gain mass or lessen it by absorbing other shadows around
therefore can shapeshift into nearly anything it wants
ice powers intensify with wrath
lack of normal biology make it immune to a lot of others powers and attacks
can interact with the world by creating a layer of ice acting like its skin and limbs

Weaknesses:

shouldn't exist
strong light can nullify its existence which briefly has it return to Laira in a stagnant state 
can't use powers or do any unnatural things when in a stagnant state
possibly can't survive without Laira for too long
any reaper could take it out of its misery
can't agree on its own purpose
can't actually feel what it touches since it's only the powers that touch others

Backstory(short version)

Age:

0: Deciding to possess a shadow was a very weird idea and led to a very big anomaly. Even an object would be better to possess, arguably, as it has an existence of its own and physical properties, while a shadow is entirely bound to its owner and has no mass or personality of its own. So when Moony started existing, the universe was broken in a very small way yet again by a mortal who was just too stubborn to obey. The shadow, prompted by the soul that thrusted itself into it, suddenly began to know, and all it knew it should've ever known was Laira, who was standing in a window staring at the moon above them. The shadow clung to that knowledge as any newborn creature would to an instinct that allowed it to survive, and both it and Laira clung to each other without understanding much of how it happened, but knowing that they both needed each other a lot.

1-34: The longer the shadow existed with a soul within it, the more the soul's traits lended itself to it, which allowed the shadow to exist even more, and allowed the soul to take over what it unknowingly created. Despite that, the core idea of a shadow couldn't be chased out of it - it was forever loyal to its owner, which was a loyalty strong enough that it held back the soul from doing what it wanted to ever since it possessed Moony. Laira, as she grew up, realised that Moony's existence must've happened by some obviously unnatural means with unknown intent, but the shadow never lashed out at her or did her any wrong, so the gently malicious personality it manifested towards others she learned to accept. In the meantime, the soul's anger and death in the icy deserts also lended itself to the shadow, and it began to ooze and later control the essence of that death in a form of elemental powers. They allowed Moony to create an even more convincing form for itself to interact with the world more. It particularly strongly wanted to interact with Laira and do what she did, so it made sure it could create music like she did with a 'voice' of its own and 'fingers' to play the instruments she owned with. The people that surrounded Laira made the soul inside stir a bit more as it remembered being abandoned by its peers, which in combination with the shadow's loyalty made it very wary of people, ready to fight if any of them tried to take Laira away from it.

34-36: Sadly, the influence of the soul spread further and inevitably affected Laira too, which after years of issues finally landed her in the closest hospital from their little house - in Bilfrith. Now Moony is warned to not stay too close to Laira at all times, and if it must, to hold back its powers. When Moony holds back on its essence like that, it reverts it to the original state of just a plain ol' shadow, which the soul can't handle for too long. But the shadow can't handle being away from Laira for too long, so it must switch back and forth between the states to maintain a balance. The shadow is hurt that it put its best friend in danger, and the soul still wants to gain enough control to become independent enough to fulfill its quest already, before it's too late.

YEAH shadow that came to life via getting possessed by Estra who's an idiot who holds a grudge over something that was her own fault goog. will probably make estra a side bio someday

boy these two are old