one thousand years ago
Celestia smirked as she walked through the halls. The guards cringed as she walked past, they had learned to fear her when she had a pleased look on her face.
"Captain Sun Spot! I am retiring for the night. Do not let anypony past these doors. Is that clear?" The royal princess spoke to her captain.
"Yes ma'am!" He responded professionally.
"Very good." She stated as she shut her lark oak doors behind her.
"Good evening, Princess." A cool voice said.
"What's good about it? Wait, who are you?" The Princess replied.
"Oh, the Princess doesn't recognize me? That's sad, considering I have been whispering in our ear for the last month. Ever since you realized how much more powerful than you Luna is. Or how much more beautiful her night is compared to your day. Sweet, perfect Celestia has become jealous!" A the voice taunted.
"Give me a name!" Celestia nearly shouted, thankful for the soundproof spell over her room.
"My name is Solar Flare. And you, Princess Celestia, are mine. Soon, your annoying little sister will be, removed from her position as the bringer of night. The ponies will soon learn to love the day, and they will marvel at MY POWER!" The sound of Solar Flare shouting made the room shake.
"No."
"What did you say?" The being was shocked by her host's reply.
"I said NO! You may have poisoned me against my sister, but I still love her. And you WILL NOT TOUCH HER!" Shouted the sun princess.
"Aw, how cute. You're defending her! Nonetheless, I need your body." The evil parasite began to fight against the ruler. Celestia felt pain and burning like she had never felt before. A blood curdling shriek left her throat, loud enough to get past her spells on her room.