Gravel is a prominent character introduced as a commander of the sixth army of the Vatlantis Empire's Lemurian invasion force. Known by epithets such as the Hero of Izgard, she is a celebrated warrior whose fame and combat prowess are recognized across the frontier. She is a blonde-haired woman with red eyes and a notable tan, standing at 168 centimeters tall, possessing a muscular yet voluptuous physique that marks her as a seasoned soldier.

Having been a soldier for her entire life, Gravel embodies a complex blend of ruthlessness and honor. On the battlefield, she is fierce and uncompromising, but she operates with a strong moral code, despising the unnecessary killing of innocents. She believes a soldier must be serious, avoid shameful conduct, and fight for the people. Away from combat, she transforms into a calm, collected, and caring individual who is deeply concerned with the welfare of her homeland, Izgard, and the greater empire. Despite her fearless warrior nature, she possesses a surprisingly shy side, particularly regarding her own body and displays of excitement, which she finds embarrassing. She is also known to enjoy socializing and having fun with her friends.

Deeply loyal to her allies, Gravel develops a significant and intimate bond with her partner, Aldia. This relationship is characterized by fierce loyalty and deep affection, to the point where Aldia treasures a scar given to her by Gravel. Her honorable nature extends to her enemies; she respects worthy opponents, does not hold grudges after a fight, and is willing to work alongside former adversaries if a common goal exists. Initially an antagonist, her path converges with the protagonist Hida Kizuna. After falling for him, she reveals a softer, shyer side, even worrying that her muscular body lacks feminine appeal. Although saddened when Kizuna chooses another partner, she respects his decision, demonstrating her pragmatic and selfless nature.

Gravel serves as a formidable initial antagonist whose strength tests the protagonists. Her arrival marks a significant escalation in conflict, as she proves capable of overwhelming elite fighters with ease. As a natural leader, she commanded respect in the Vatlantis military, winning numerous battles before a peace treaty was signed. Following the war and the closure of the dimensional entrances, she makes the difficult but dutiful decision to remain in her world to rebuild her country, becoming the President of Izgard. This transition from a celebrated commander to a political leader highlights her wisdom, leadership skills, and commitment to the greater good. Her development arc moves her from an enemy of the main characters to a powerful ally and eventual leader who prioritizes her people's future above her personal desires.

In terms of abilities, Gravel is an immensely skilled combatant, considered one of the best in Atlantis, capable of rivaling elite guardians and master swordsmen. She possesses tremendous stamina, enhanced speed and reflexes, and keen intelligence that she applies to strategy. Her magical equipment was formerly the Heart Hybrid Gear known as Zoros. This gear granted her vast raw physical strength, incredible speed, and immense durability, allowing her to survive grievous wounds and continue fighting. Her signature weapon is a massive gun-sword that functions as both a melee blade and a particle cannon for ranged attacks, supplemented by four wing-like particle cannons. Her most powerful armament is the Corruption Armament Sword Gatling, a devastating combination of rapid-fire cannons and a massive sword capable of inflicting massive damage even on other Heart Hybrid Gears.