[Worldview]
This is a fantastical world centered around stars, the sky, and wings.

In this world live beings called “Hoshigo,” who are different from humans. Hoshigo are born from the stars, bear wings on their backs, and live by flying through the skies.

In the sky exists a path known as the “Seiro,” where the magic of the stars flows. The Seiro connects various regions across the world and serves as an important link between the stars and the earth.

Furthermore, in each place there stands a special light called the “Seito.” The Seito delivers starlight to the world, preventing darkness from spreading. Thus, for the Hoshigo, “flying” is not merely movement or freedom; it is also about traveling along the Seiro, safeguarding the Seito, and watching over the world.

[The Star Guards and the Star Research Institute]
The “Seiei” are Hoshigo directly under the royal family. In addition to patrolling the Seiro and protecting the Seito, they also undertake the task of investigating unknown ruins discovered during their travels.

Ancient records and artifacts found in these ruins are sent to the “Seirin,” an institution dedicated to studying the origins of the Hoshigo, the magic of the stars, the Seiro, and ancient civilizations.

In essence, the Seiei are “those who travel the world and make discoveries,” while the Seirin are “those who unravel history from what has been discovered.”

[Star Rank and “Names”]
The Hoshigo possess a social rank known as the “Seii.” Those born in earlier times often hold higher Seii ranks because they have accumulated more experience and knowledge. This rank does not simply reflect strength; rather, it signifies experience, wisdom, and one’s position within society.

Moreover, in Hoshigo society, “names” carry special meaning.

Formal relationships—such as master and disciple or partner—are granted distinctive names. In some cases, such bonds may even receive divine blessings.

However, not every bond bears a name.

They simply stand side by side.
They fly in the same sky.
Even without words, they understand each other’s wings.

Such “nameless bonds” also exist in this world.

Once upon a time, there were two Hoshigo who always flew together, side by side.

Though they were not official partners, those who witnessed their flight, like a pair of wings moving as one, came to call them thus:

—“The Starling with Twin Wings.”

This is a story about stars and wings, those who protect the world, and the interplay between “relationships with names” and “relationships without names.”