Celes Ashrain is the main heroine of the story. At nineteen years old, she is a woman of extraordinary beauty, possessing golden hair and blue eyes. Her lineage is notable, as she was originally a princess from the country of the High Elves before later serving as the captain of the Order of Holy Knights in the nation of Nea. Her famous beauty is such that it is said to drive many people mad, and even items she once owned are treated as national treasures; this combination of looks and skill has made her name known worldwide and a target for numerous powerful figures.

Her personality is defined by a very serious and dutiful nature. She is an honest individual with a strong sense of justice who always strives to do the right thing and keep her promises. This earnest and moral character leads the protagonist, Touka Mimori, to consider her a good person and place his complete trust in her. In addition to her principled character, she is highly intelligent and possesses remarkable swordsmanship, honed from her time as a knight captain, which also means she understands how to fight in a coordinated, organized manner.

Celes Ashrain’s backstory is marked by tragedy and flight. After the nation of Nea was attacked and forced to surrender to the Bakuos Empire, she was forced to escape abroad with the help of an ally named Cattleya. She does not know that she herself is the true reason her country of Nea was destroyed, a secret that remains a crucial part of her personal history. To hide from her pursuers, she lived in exile using the alias Mist Barukas. By employing the power of spirits, she can change her appearance and combat attire, effectively disguising her true identity. However, when she channels a significant amount of this spirit power into maintaining her disguise, her fighting strength is greatly diminished.

Her journey becomes intertwined with Touka Mimori’s when she meets him during her exile. At the time, she was still in her disguised form. However, the pursuers sent after her were all defeated by Touka, who happened to be present, an event that led them to gradually begin acting together. After this encounter, she continues to travel with him, keeping her real identity a secret for a long time while supporting him as a close and trusted partner. As the story progresses, Celes develops romantic feelings for Touka, becoming completely devoted to him, and fans consider them the story's established main couple. In addition to her sword skills, Celes possesses other unique abilities, including the power to use spirits and a specific skill that allows her to see through lies, which becomes important during key moments of the plot.