1) Artemis Origins:

Queen Celestia walked to the balcony, ready to rise the Sun like she had always done for the past millenium; before she could get there, a shooting star crossed the sky but didn't finished her journey across the night sky, instead, it landed on the balcony. "Luna!" Celestia thought and teletransport herself to the balcony.

The speed star travel could cause a lot of damage or even an explosion, but…this one didn't even make a sound. Celestia was in the balcony, she turned around to see if her sister was okay, but instead of looking at her sister, she noticed something was glowing next to Empress Luna; there was a brief moment of silent between the two, both looking at each other.

Before any of them could say a word, the glowing star began to slowy fade and reveal the silhouette of a foal. She was white and her mane had small stars just like Luna's, there was still some glowing light coming from her little body. Luna looked at her warmly and covered her with her wing, then looked up to Celestia with worried eyes.

"Sister, I know you have a lot of questions but please, let me explain" Luna said with a hurry, but Celestia still spoke first. "Luna, what have you done? What did you do to this little foal?"

It took Luna a moment to finally talk "This foal, wasn't exactly a foal…I've been waiting many moons for a particular star to show up again in the sky just so I could-" before she could finish, Celestia said furiously confused "Don't tell me you used the ancient spell Starswirl forbid us to perform!? You know how dangerous it is to do such thing, using magic to create living creatures out of things is forbidden and you know that!"

Luna was about to reply but Celestia kept talking "And most importantly, you took a star to do that! Think about the alterations you just caused! The stars will realign and many, many things will change for the future!"

Luna placed the foal in a protection bubble and stand up in front of her sister "You think I don't know that? I'm the ruler of the night, of course I know that! But…it's just that, I wanted to have a foal of my own but never found the right pony to love". Luna walked towards the edge of the balcony, Celestia's anger began to fade as Luna continued to talk "I even tried talking with Princess Cadence, just so I could know if there was even a pony out there meant for me" there was silence "…there was none." Celestia's anger banished, she stood beside Luna and opened her wing to confort her.

"That's when I remembered about the life spell, after doing some research I found out that stars have enough magic to create an alicorn foal. The strongest of them all was the constellation Sagittarius, but I had to wait until it was close enough to us. That's when I performed the spell and the star fell to the earth" Luna took the foal out of her bubble and carried her in her hooves "I know what I did was wrong, but there was no other way".

Celestia turned her gaze to the foal "I'm sorry that love never crossed your path, and I forgive you for what you just did; just remember that there will be consequences for what happened tonight and we'll have to take responsability for whatever happens in the future". Luna nodded and started to walk away; before she leaved, Celestia asked her while raising the Sun "Have you thought about a name for her yet?" Luna replied "I took a star from Sagittarius, so I wanted her name to be related, how about…" she smiled "…Artemis".

2) Artemis was born as white as the moon, as the years passed, her coat began to change to a darker color. This is Artemis when she was 8 years-old

3) When Artemis was little, she fell ill and nopony knew why. It was strange because during the night she was healthy but as soon as the sun touched her coat she would feel sick again. As a prevention, Empress Luna would cover her from the light and the outside world. One day, while Celestia was taking care of her, Artemis asked her Aunt if the Sunrise was as beautiful as her books would describe; Celestia felt bad for her and one day she sneaked her to the balcony so she could see the Sunrise just before the light touched Canterlot.

Of course, Artemis felt ill even so but at least now she had a goal, to see the Sunrise and feel the warm of the sun.

4 & 5) When Artemis reached 14 years old, she started to feel so weak that she couldn't get up. One day, her cousin Princess Eris discovers that Artemis has been using her magic to be able to stand the sun light, that way she would get use to it; of course, Eris tells this to her mom and Celestia tells Luna; that's when Luna decides to ask Sunburst what can be done about it, since he studied along side Starswirl; in the end, they find out that Artemis, being a star, naturally becomes weaker during the day. To fix this, Luna extract a lot of the magic that Artemis had stored because of the star and the body of Artemis turns really dark, even darker than Luna's.
Now Artemis has the same amount of magic that any other alicorn would have, she started studying magic with her mother so she could get used to lesser magic.