Eguille is a supporting character in the anime Tales of Zestiria the X, serving as a leading member of both the Sparrowfeathers merchant guild and its covert counterpart, the Scattered Bones assassin guild. He is a trusted and integral part of what he and his comrades consider their family, a group formed from the remnants of a famous mercenary band known as the Windriders. His past is marked by betrayal, as the Windriders were disbanded after being framed for treason by Imperial Prince Konan of the Rolance Empire, an event that led to the execution of their leader and Eguille's own arrest, from which he managed to escape.

Physically, Eguille is a tall man with short, slightly messy gray hair, a visible beard on his chin and cheeks, and light blue eyes. His typical attire consists of his Sparrowfeathers captain uniform, which includes a brown, bolero-length leather vest worn over a black shirt with a red tie, with a long-sleeved white shirt as the bottom layer, complemented by dark black pants and knee-high boots. In his role within the guild, Eguille is a figure of responsibility and strategic thinking. According to Rose, the leader of the Scattered Bones, he acts as the eyes, ears, and brain of their operation, handling all matters related to their business and ensuring the safety of their family, such as by searching for a new hideout when necessary.

Eguille's personality is defined by deep loyalty and unwavering trust. Like the other members, he views the guild as his family and shows complete faith in Rose's leadership, stating that her judgments are the team's own and never questioning her choices. He serves as a mentor to Rose, having taught her everything she knows about martial arts and stealth. While his primary allegiance is to his family, he is not blindly trusting of outsiders, as demonstrated when he doubts the Shepherd Sorey's true intentions and confronts him in battle on the road to Rayfalke Spiritcrest to test his resolve. This protective instinct defines his role in the story, as he is frequently seen managing their public front as merchants or acting in the shadows to eliminate threats.

Within the anime's narrative, Eguille's motivations are tied to the survival and honor of his adopted family. A significant subplot involves his quest for revenge against Prince Konan, the man who betrayed the original Windriders. It is Eguille who discovers Konan's location and informs Rose, setting in motion a long-awaited confrontation. He also plays a key role in protecting the younger members of the group. When the Scattered Bones are ambushed by Rolance soldiers, Eguille shields the young member Talfryn with his own body, allowing the boy a chance to escape and find Rose, even as Eguille and the others are captured. This act of self-sacrifice highlights his development from a capable mercenary to a paternal figure willing to risk everything for his family's future.

In terms of abilities, Eguille is a highly skilled combatant, proficient in martial arts and assassination techniques. His primary weapon of choice is daggers, though in the Tales of Zestiria the X anime adaptation, he is depicted wielding a sword. As a human without the ability to perceive seraphim, his combat style focuses solely on tangible, physical foes. His skill is sufficient to serve as Rose's substitute in leading the group and to act as her teacher, establishing him as one of the most capable non-seraph fighters within the setting.