The Keeper of the Immortal

Once upon a time, in a world where magic was more than just a fantasy, there lived a powerful immortal being named Arion. He had been roaming the celestial boundaries for so long that time had lost all meaning to him. He possessed an extraordinary power - the power of immortality, which he could gift to a single chosen soul.
However, with this blessing came a curse. He was doomed to eternal solitude, never to form bonds of friendship or love lest his secret was revealed, and his power threatened. The only company he had was his keeper, an old wizard named Arcanus. Arcanus was a wise man who was tasked with the charge to protect and guide Arion, a duty passed down through generations.
Arcanus lived in a secluded tower concealed in the misty highlands, detached from the material world. He was a loner, with only the books and stars for company, spending years deciphering celestial patterns and ancient spells. He taught Arion the rules that came with his powers and explained the consequences of sharing his immortality.
Despite the confinement of his state, Arion was curious, filled with a burning desire to experience the world outside, to feel, and to love. He often stared into the vast expanse, the world thrumming with life underneath, and longed for the day he could be a part of it.
On one such day, while Arcanus was engrossed in his books, Arion slipped away into the world unknown. He used his power to take a human form and began his journey unexplored, a journey led by yearning. Along the way, he encountered people of all kinds, each with unique stories and experiences. He encountered joy and despair, laughter and tears, love and betrayal.
Among these numerous encounters, Arion met Eleonora, the daughter of a poor baker, and against his better judgment, fell in love. Despite knowing the consequences, he revealed his true form to her. Eleonora, taken aback, at first, soon realized the intensity of Arion's affection and reciprocated his feelings.
Together they shared numerous moments of joy and love, with Arion's heart feeling contentment he had never known before. However, as feared, word got out about Arion's extraordinary abilities of immortality, inciting the wrath of the King, who sought immortality for himself.
Arion was captured, and the King demanded him to grant him immortality. When Arion refused, Eleonora was threatened. In his need to save her, he broke the cardinal rule and granted her immortality. The mere touch of Arion transformed Eleonora into a being of eternal life.
Suddenly, a bolt of light shot across the room, and there stood Arcanus. He was furious at Arion's reckless actions. The King, sensing additional power, demanded Arcanus grant him immortality too. In a swift move, Arcanus cast a powerful spell, and Arion and Eleonora vanished, leaving an infuriated King behind.
Arion found himself back in the celestial realm, Eleonora by his side. Arcanus told Arion that he had created an imbalance in the world by bestowing immortality onto a mortal. As punishment and atonement, Arion's immortality was taken away, and he was made to live as a mortal with Eleonora on a distant star, far away from mankind.
Arion, regretful of his actions, accepted his fate, realizing that even as a mortal, he was happier with life that had an end but was filled with love. From there on, he lived his days in peace, cherishing every moment with Eleonora. His tale remains as a reminder that immortality is a luxury, but love and companionship are the true blessings of existence.
Arcanus returned to his solitude in the tower, waiting for the next immortal to be born and to pass on the profound lesson he had learned from Arion.