Explanation

Aether headed to the office of the Commander of the City Guards.

Creeak!

Without even bothering to knock, Aether entered the office.

The office only had a desk in the center and a whole wall of books behind the desk.

Stein, the new commander of the city guards, sat at the desk, dealing with some documents.

As the door opened, he frowned and sharply looked at the door.

"Who dares enter without knock..." But as Stein saw who it was, the corner of his mouth slowly curled up into an arrogant smile. "Ohh, look who decided to get back to work after so long?" Stein taunted. "But Aether, this is the commander's office. You can't just enter without knocking."

Aether ignored Stein's taunt. 

Swoosh!

A white letter appeared in Aether's hand, and he threw it at Stein.

The letter spun in the air and landed on the desk before Stein.