Aquasteed Marineforest is the Crown Prince of the Marineforest Kingdom, a powerful neighboring realm in the romantic fantasy narrative. He is a character originally from an otome game titled Lapis-Lazuli Ring, where he serves as a main capture target in its sequel, but his most prominent role is within the story that unfolds after the game's standard conclusion. Physically, Aquasteed is distinguished by his beautiful dark blue hair and captivating golden eyes, which complement his overall noble and refined bearing.

As a personality, Aquasteed embodies a balance of classic princely elegance and genuine emotional warmth. At first glance, he appears as the idealized royal archetype: calm, kind, and impossibly refined. However, his kindness is never portrayed as a political tool or a superficial gesture; it is deeply sincere and rooted in his true character. He is decisive and chivalrous, famously demonstrating these traits when he interrupts a public condemnation to propose marriage without a moment's hesitation. He is also quietly observant, having noticed and admired Tiararose long before their official engagement, watching her expressions and quiet strength during their time together at the academy. While his adoration for Tiararose is often described as bordering on obsession, it is a healthy and mature form of devotion. He is protective and displays jealousy when her safety is threatened, but this is rooted in concern rather than a desire for dominance or ownership. He consistently respects her boundaries, listens to her choices, and focuses his energy on ensuring her happiness.

Aquasteed's primary motivation is his deep and unwavering love for Tiararose Lapis Clementille. He harbored these feelings for a considerable time while she was engaged to another prince, preventing him from confessing his true intentions. The pivotal moment of his story occurs at the graduation ceremony of the Lapis-Lazuli Kingdom, where Tiararose is falsely accused, has her engagement publicly broken, and is subsequently banished. Seeing her now free from her previous ties, Aquasteed immediately steps forward, publicly announces his long-held affection, and proposes marriage to her on the spot, effectively rescuing her from her condemned fate. This act defines his role in the story as not just a love interest, but the emotional backbone who overturns the villainess's tragic destiny. He is the prince who offers not a single act of salvation, but a continuous, devoted partnership.

Throughout the narrative, Aquasteed's relationship with Tiararose is the central focus, characterized by a mutual and deeply affectionate bond. He is frequently seen doting on her openly with compliments, soft smiles, and public displays of affection. His devotion is put to the test in episodes such as when Tiararose is kidnapped by forest fairies. Aquasteed, driven by his love for her, fearlessly ventures into dangerous territory, using secret passages known only to royalty and overcoming various traps to storm the throne of the Forest Fairy King to rescue her. This event not only showcases his bravery and resolve but also deepens the couple's mutual understanding and strengthens their resolve to remain together. Aquasteed's character develops through these trials as his love proves to be both his greatest motivation and a source of strength.

In terms of abilities, Aquasteed is not merely a decorative prince. He is highly talented and intelligent, having been trained from birth to rule his kingdom. He is skilled in swordsmanship and is adept with magic, making him a capable fighter in addition to a diplomatic leader. His resourcefulness is highlighted by his knowledge of secret paths and his ability to navigate treacherous environments. He also possesses the diplomatic skills and foresight expected of a crown prince, forming alliances and making decisive actions that benefit his kingdom and those he cares about. His innate charm and noble bearing make him a prominent figure, but it is his genuine compassion and unwavering integrity that truly define him as a leader.