Rosetta appears as a mysterious human beauty during the crew's travels, yet embodies the primal beast Rose Queen. She holds crucial knowledge about the world's deepest secrets, including those vital to the protagonist's quest, but deliberately speaks in generalities. She avoids direct revelation, preferring to act as a guiding bystander guided by her own convictions. Aware of the Black Knight's intentions, she rejects them, steering events according to her independent judgment.

Her existence spans centuries, having lived through the Skydwellers' war against the Astrals. Throughout this time, she remained inseparable from Yggdrasil, a bond lasting hundreds of years. This ended when Gran's father subdued her and invited her to join his crew alongside his other companions, cementing her deep connection to the world's hidden lore and conflicts.

Rosetta displays affection through playful interactions, especially with Yggdrasil, whom she embraces with "love hugs" and offers to share a pocky kiss. She forms bonds with other crew members like Io, praising Io for speaking her mind to ease worries about being harsh toward Pommern and later teaming up with Io to battle the primal beast Fenrir. Her interactions extend to spin-offs like *Grand Blues!*, where she humorously mimics Cerberus using dolls (including the dragon Vyrn, whom she orders to call her gorgeous) and performs a show for Lennah after receiving compliments. She harbors a preference for attractive individuals regardless of gender, enjoys gardening, and expresses a distinct dislike for machines.

In combat, such as in *Granblue Fantasy: Relink*, her abilities focus on manipulating roses. She plants roses that autonomously attack nearby foes. Her skills allow repositioning these roses, causing them to explode based on their growth level, or granting herself defensive buffs like Stout Heart and Iron Maiden, making her a hybrid support and damage dealer requiring tactical rose placement management. In the original game, she wields wind-attribute powers, using skills like "Thorn" to inflict poison and wind damage, "Helleborus Tiara" to evade attacks, and "Crimson Dress" to heal herself while boosting attack and defense. Her charge attack, "Sullen Rose," deals significant wind damage. An alternate SSR version further emphasizes rose mechanics through her "Rose Barrier," which gains stacks when she takes damage and provides team-wide buffs when released.