Rosa is a young woman who tends to the interior gardens of the Villa near Dracula's Castle. Some time prior to the beginning of the game, Rosa had been turned into a vampire and continues to inhabit this mansion. She encounters both Reinhardt and Carrie in the Villa's rose garden, where she can be seen tending the roses (by watering them with blood). Rosa advises the adventurers to leave, but otherwise makes no effort to impede their journey.
For Reinhardt's quest, Rosa becomes a pivotal character after their initial meeting; encountering him a second time when he prevents her from committing suicide by sunlight after his journey through the subterranean caves beneath the castle. Desperately wishing to be free of her vampirism, she begs Reinhardt to kill her, but leaves after he refuses.
Following his battle with the Behemoth in the Castle Center, Reinhardt encounters Rosa a third time when she is compelled by Death to fight him. She is beaten, but again Reinhardt refuses to kill her, considering her an innocent. Rosa is then spirited away by Death, who promises that in time her curse will take her over completely.
Later, at the top of the Clock Tower, Death lays a trap for Reinhardt and nearly succeeds in cutting him down, when Rosa appears out of nowhere and throws herself between Reinhardt and Death's scythes, taking the blow for herself. Mortally wounded, Rosa is comforted by Reinhardt in her final moments, as he prays for God to grant her forgiveness and promising salvation before she fades away. Rosa's sacrifice fuels Reinhardt's rage and, despite his opponent ridiculing the notion of a vampire hunter grieving for a vampires' death, promptly defeats Death before continuing on to the final battle with Dracula.
After Reinhardt destroys Dracula's true form, the castle crumbles to the ground and the evil recedes from the land. Through divine benevolence, Rosa is given a second chance at life and is resurrected in front of Reinhardt. The two share a moment on the cliffside overlooking the ruined castle before setting off, indicating a potential romance between to the two.
Whether it is because she is only a recently turned vampire or she has incredible willpower, Rosa appears to be able to resist the darker impulses of the vampire curse. During her first encounter, she shows no aggression and could almost be considered friendly toward Reinhardt and Carrie. Only through direct compulsion by Death does she lose her self control and attacks Reinhardt. Further evidence of her willpower is indicated by her self sacrifice to save Reinhardt from Death's ambush, and also by her attempt at suicide by intentionally exposing herself to sunlight.
In combat, Rosa wields a rapier, which she will use to occasionally attempt to slice her opponent. She also has a variety of demonic related abilities, such as mid air hovering and summoning fire roses. She can also create a small shockwave centered around herself, which expands outwards. If caught unprepared, Rosa can easily overwhelm an opponent. However, given her passive nature, it is unlikely Rosa has had any real combat training and is only acting under Death's compulsion when attacking Reinhardt. Her supernatural abilities were most likely due to her vampire state, so it is doubtful that she retains any of them after her resurrection.
- See also Rosa Artwork.