Once upon a time in an enchanting world filled with mystic adventures and dazzling magic, there lived a boy named Leo, who was reincarnated from Earth.

Despite being born in a world of magic and might, Leo found himself at the weaker end of the spectrum, he couldn't perform even the simplest of spells.

But, instead of giving up, his heart braved, and he decided to change his fate. He looked for a way to survive in his newfound world.

One day, Leo came across an ancient book, inside which he found a spell promising to bring forth his most powerful protector.

The summoning spell required a colossal amount of energy. Despite his limitations, Leo decided to give it a try, stirring up all his strength.

As the last word left his mouth, a bright light enveloped the room. When the light faded, there stood a radiant lady in armor, with an aura of invincible strength.

The lady was Stella, his older sister from his previous life. She was known to be the Apex Champion. Though warlike, she was extremely protective of her little brother.

Meeting Stella again, Leo felt a surge of emotions; joy from reunion, safety in her strength, and concern, for it was his weakness that forced this situation.

Stella was equally surprised. This was a world far different from their previous life, but her love for Leo was unchanged. Her obsession with keeping him safe remained intact.

She assured Leo that no harm would come to him as long as she was there. She would protect him even from the tiniest of problems, which sometimes annoyed Leo.

But he also felt thankful for having Stella by his side; his big sister, who was not only his protector but also his greatest source of comfort in this strange world.

Leo's life took a swift turn. He was now living under Stella's wings, allowing him the freedom to understand and face the odds of the magical world.

Together, they embarked on quests, faced mystic beasts, decoded ancient languages, and undertook perilous journeys through treacherous terrains.

Stella, with her unwavering strength, handled every calamity, while Leo, owing to his weakness, shrank away from physical battles. Instead, he focused more on honing his magical skills.

Their bonding grew ever so strong, transcending beyond the boundaries of their past life into the present. Their love for each other was their firmest pillar of support.

However, they knew this respite wouldn't last forever. Sooner or later, Leo had to face the real world, and Stella might not always be there to protect him.

One day, Stella told Leo about an ancient legend; the prophecy of a hidden power that would help him find his rightful place in the magical world.

Despite his fear, Leo decided to venture on this dangerous journey. He had been relying too much on Stella, and it was time for him to step up.

Stella, understanding Leo's resolve, prepared him for the journey. The love for her brother turned into a strong motivation to train him.

After weeks of grueling training, Leo was finally ready to embark on his quest. Stella, despite her worry, trusted Leo and allowed him to leave.

Leo, dressed in his new armor, left for his journey. His heart pounded with fear, but the thought of proving himself, and Stella’s love, kept him going.

After countless hardships and near escapes, Leo finally found the hidden power, a magical artifact that could amplify an individual's magical prowess.

On his return, Leo was stronger than he ever was. He no longer feared the magical world, and his sister's shadow over him seemed to have faded away.

Stella was overflowing with joy and pride. Leo had managed to overcome his weakness and step into a world of strength and confidence of his own making.

Their journey continued, but this time, they fought side by side. Leo, no longer the weak little brother, but a strong companion protecting his sister.

Stella was no longer just a protector but a sibling proud of her brother. Their bond transformed from overprotectiveness to mutual respect and reliance.

Though Stella's obsession with Leo's safety didn't entirely fade, she learned to let Leo face his battles. It was a significant change for both of them.

And so, their tale continued. They faced new dangers, conquered fears, and grew stronger together. Yet, the magical world kept unraveling more mystic secrets.

Through these trials and tribulations, Leo found his place in this magical world, and Stella found her freedom from the worry for Leo.

As the sun settled down, and moon took its place, brother and sister continued with their adventure, ready to face whatever the magical world had in store for them.

Their tale became a legend among the folks, a symbol of love and strength. And they lived, not happily ever after, but challenging every 'after' with their undying spirit.