Part of my Redemptiverse idea
 
I decided to make Cozy Glow the Luna of this AU. In this universe, she is the princess of light and hope and was Princess Abacus’s first student. Being her first student, Abacus wanted to make sure that the young orphan she adopted became someone great. As a unicorn, her special talent was light manipulation but what ascended her to alicorn status was her compassion and ability to spread hope and comfort to those in need.
 
She and Abacus protected and led Equestria for many years but as time went on, Glow became more and more self conscience. Wanting to be as powerful and loved as her mentor. The insecurities turned to bitterness and then to hatred as Abacus began to refuse to teach her about the stronger magic in the world. Abacus wanted to protect Glow from the darker mystical items and practices but only made her more curious and more angry when she refused to help her.
 
Glow started to dabble in shadow magic and became corrupted from it’s power, wanting to make it stronger. To make sure that he newfound powers would always stay at their strongest, she began taking away all the light in equestria. Light was the only thing that could weaken shadow magic. Before she could fulfill her goal, Abacus sealed her away in tartarus for 1000 years. During that time, Abacus searched for some way to save her fallen student.
 
1000 years later, during the festival of lights, Glow, now going by Queen Abyss, escaped tartarus and threatened to steal all light in equestria, even light from both the moon and sun, and rule equestria alone. She was stopped by Starlight and her new friends using the elements of harmony and freed from the shadow magic that night. She apologized to her teacher and was welcomed back with open arms to equestria.
 

 
If you want to know, I thought an interesting idea would be that shadow magic is at it’s strongest during the darkest night of the year and Abacus started the festival of lights to make sure that Abyss couldn’t get too powerful and escape tartarus. What she didn’t know was that Abyss had been storing up all her magic in tartarus and after 1000 years, she finally had enough to break free despite the festival of lights going on all around equestria.
 
for the design, I ditched the Shirley Temple curls and gave her a majestic spiral effect, as well as having one of her hair strands always be glowing a little. I also changed her cutie mark to better match her name and role in this AU.