Harmony Grace stands tall at approximately 150 mm in height, depicted in a poised, upright stance wearing a white and pale-silver light armor set that blends elegance with battlefield practicality. The helmet is absent to reveal a calm expression and determined blue eyes, with pale hair peeking from beneath the armor edges. The armor features slender plates on the shoulders, chest, and thighs, accented by delicate blue and gold inlays and translucent pink energy accents at the joints that hint at an inner power core. A flowing cape or robe piece drapes behind, balancing martial aesthetics with reverent grace. Surface textures range from glossy polished armor to matte fabric-like underlayers, with fine engravings along the trim. The overall silhouette emphasizes agility and balance, reflecting Harmony Grace's role as a guardian who fuses technology with a sacred creed. Small accessory pieces compatible with MMS joints allow dynamic posing.

In the Busou Shinki universe, Harmony Grace is a devoted protector created as part of the Sister class to embody mercy, discipline, and steadfast courage. As a Light Armor unit, she merges holy symbolism with advanced modular armor to defend her operator and allies from digital threats and physical confrontations. Her backstory describes training under stern mentors, learning to navigate conflict with calm resolve, offering shield energy and healing aura when needed. Her mission is to safeguard the balance between order and freedom within the networked city where Shinkis operate. Harmony Grace trains relentlessly, refining reflexes and teamwork, collaborating with other MMS figures in squad-based battles. Her arc centers on trust, sacrifice, and the belief that mercy can be a form of strength in warfare, guiding teams with quiet resolve.