|“||The moon tonight is red. You will know death.||„|
— Remilia Scarlet
Not much is known about Remilia's earlier life. She claims to be a descendant of Dracula himself, but this is most likely false and just made up to play herself up.
Arrival in Gensokyo
Remilia and her mansion appeared one day in Gensokyo, during an unspecified time. She went on a rampage, eventually being halted by a powerful yet unidentified youkai. They came to the agreement that Gensokyo would give her humans for food (it's unspecified where the humans come from other than them being from the outside world) in exchange that she not attack the humans of Gensokyo. This agreement eventually lead to the creation of the Spellcard Rules, now widely used throughout Gensokyo.
The Scarlet Mist Incident
Some time in 2003, Remilia sent a red mist over the skies of Gensokyo to block out the sun and allow her to roam free regardless of time of day. This caused local shrine maiden Reimu Hakurei and local mage Marisa Kirisame to investigate, eventually leading to Remilia battling the two and losing. Due to Spellcard Rules, she was forced to withdraw her mist.
Remilia often gives off the image of a terrifying vampire mistress, an image she treasures and preserves greatly. However, this is not entirely true deep down, as she is still mentally a child, although a quite polite child. She also has a reputation among youkai for being charismatic, but this in truth only amounts to her being somewhat of a large ham, and this reputation likely stems from the fear and respect the youkai have for her.
Due to her reputation, she often makes things up. For instance, she pretended to be a monster so Aya Shameimaru would put it on the news, and she claims to be a descendant of Dracula himself.
Due to her immortal life, she tends to get easily bored, almost to a fault, to the point where she will let someone manipulate her despite knowing exactly what they're doing just so something interesting will happen.