Asterote Reighe, who goes by the nickname Aster for short, is a character known for his imposing physical presence and carefree personality. He is a towering man, standing over two meters tall with a muscular, robust build. He has blonde hair cut to ear length, and his eyes are typically depicted as closed or not visible. His full name, Asterote, is the Japanese pronunciation of Astaroth, though the story assigns no particular narrative significance to this connection.

By profession, Aster works as a demi-armor hunter, a type of mercenary who specializes in hunting powerful mechanized armors known as demi-armors, wielding only his own strength and weapon. His chosen weapon is a massive sword, grossly oversized and even larger than his own great height, which he swings with tremendous power in combat. His fighting style reflects his straightforward and brute-force approach to problems.

Aster's personality is defined by a love for a free and unburdened life. He is fun-loving, opportunistic, and constantly seeks enjoyment, whether through revelry, strong drink, or the company of beautiful women. He possesses a general disdain for authority and rules, a trait that led him to abandon his past. Before becoming a mercenary, he was the son of a regional lord, with an older half-brother. Unwilling to tolerate a life of restrictions and obligations, he left his family and home behind to forge his own path. This background explains his fierce independence and his rejection of structured society.

In his relationships, Aster is most closely allied with Solude Schfoltzer. The two are best friends and partners, described as partners in crime. Despite having wildly different personalities, they are united by their shared love for a good time and their mutual hatred of authority. Beyond this partnership, Aster develops a persistent and deep infatuation with the protagonist, Maze. He has a huge crush on the female version of Maze, which becomes a recurring motivation for many of his actions and his decision to join her on her journey. While he is fond of women in general, his attraction to Maze is notably more significant.

Within the story, Aster serves as a supporting fighter and a source of comic relief. He joins Maze and the princess Mill Varna on their travels, contributing his immense combat skills and a lighthearted, carefree outlook to the group dynamic. He acts as a dependable ally in battle, using his giant sword and raw strength to protect his companions and fight their enemies. However, his character remains largely static throughout the series. His personality, relationships, and behavior patterns show little substantive evolution, and the narrative does not explore his deeper motivations or any significant internal conflicts beyond his immediate desires for pleasure and his affection for Maze. He consistently fulfills the role of the strong, loyal, and fun-seeking friend without undergoing a personal journey of change.