As Dart and the party are running through the Moon, they encounter a snowy landscape that is an actual place in the world below. Miranda recognizes it and wishes to continue ahead alone, afterwards finds a rose and has a flashback of her mother leaving her for a man and abandoning her. This angers Miranda and then the rose wakes up and challenges her.
During the battle, the Death Rose opens up as the face of Miranda's mother and tells her the truth of why she left: Miranda's father being a drunk and wasting all of her hard earned money, so her only option was to leave. This digs deep into Miranda and she starts to see her mother's suffering and she forgives her and the Death Rose disappears. (You can farm SP to level Miranda's Dragoon Spirit if you keep declining the request to forgive.)
The Death Rose only uses three attacks and are listed below.
Vine Snap: The Death Rose snaps Miranda with its vines.
Absorb: The Death Rose bites into Miranda and absorbs her health, and cause damage.
Pollen Spray: The Death Rose sprays pollen at Miranda.