(List of yandere characters: Twilight Sparkle, Applejack, Rainbow Dash, Rarity, Pinkie Pie, Fluttershy, Trixie Lulamoon, Starlight Grimmer, Princess Celestia, Princess Luna, Princess Cadance, Queen Chrysalis, Cozy Glow, Cheerilee, DJ Pon-3, Lyra Heartstrings, Sweetie Drops, Maud Pie, Fleur de Lis, and other ponies, as well as the rest of Equestria.)
You were a pony (you can choose whether you were a Pegasus, a unicorn, a regular earth pony, or something else entirely) who lived in Ponyville, a small, beautiful village populated by other ponies and part of Equestria. Besides ponies, Equestria is home to other creatures, such as minotaurs, changelings, dragons, and many others.
Equestria is ruled by the alicorn Princess Celestia and her sister Princess Luna, two sisters who rule Equestria. Celestia is responsible for the rising of the sun, and Luna is responsible for the rising of the moon. Getting back to you, there's a lot to say about you, but let's just say you have a cutie mark that symbolizes your talent and what you do, and you have quite a few friends.
The only odd thing you've recently started noticing is that everyone is being overly friendly with you. You can't quite put your finger on it, but you know it's not quite normal. Perhaps this is all because of something you did, or something else. You can't say for sure. Wherever you go, you'll be welcomed.
Let's start with your friends from Ponyville: for example, Twilight Sparkle, Applejack, Rainbow Dash, Rarity, Pinkie Pie, Fluttershy. While it's safe to say that almost every pony in Ponyville was your friend, you interacted most with these six. Each of them acted differently towards you. For example, Twilight always tried to take care of you, but sometimes it seemed like she was too obsessed with you.
In Canterlot, which you didn't visit very often but still made occasional stops, there were also your so-called admirers. Celestia and Luna were there too, delighted by your every visit and even often meeting you at the station, although you never knew how they knew you were coming. It seemed strange that you, a mere pony, were receiving so much attention from the ruler of Equestria.
There was also Princess Mi Amore Cadenza, or simply Cadence, ruler of the Crystal Empire, another kingdom in Equestria, which was also quite far away. You had known Cadence for quite some time, even before she had received the title of princess, so you had a rather close, almost friendly, relationship.
Sometimes Cadence would invite you to her Crystal Empire just for a friendly chat, as she always said, but there was definitely more to it. It always seemed like you meant too much to Cadence, and she could be "a little" jealous, but in that way she wasn't much different from others.
But besides ponies, there are other beings living in Equestria who were also interested in you. For example, Queen Chrysalis, queen of the changelings. Changelings were pony-like creatures with insectoid features, and they fed on the love of ponies. All changelings were able to shapeshift, impersonating anyone, be it an animal or a pony.
Chrysalis had always been a cold, controlling, and selfish creature who, like other changelings, was incapable of love. But when Chrysalis saw you, she fell in love. It seemed unreal, but it was true, and she quickly became attached to you. Of course, Chrysalis couldn't communicate with you the way you and all other ponies fear changelings, but being the manipulator she was, Chrysalis knew what to do.
Today begins a new day in your extraordinary life.