As a White Mage, Rosa can cast White Magic. She learns every White Magic spell in the game, although some she learns at levels different from Porom. Her other two abilities are Aim and Pray. Aim allows Rosa to charge up a slightly stronger attack that never misses at the cost of executing slower, and is only usable while Rosa is equipped with a bow. Pray restores a small amount of HP to allies if successful, roughly equivalent to a Cure spell.
In the 3D remake release, Pray has a higher chance of success and restores both HP and MP, the amount healed based on a percentage of each party member's max HP and MP. Rosa also learns her White Magic at different levels. In the Advance and Complete Collection 2D releases, completing Rosa's Lunar Trial rewards her with the White Ring, which upgrades Pray to Miracle. Miracle casts Cure on a failure, Cura normally, and randomly casts Curaga and Esuna.
In the Advance and Complete Collection 2D versions of Final Fantasy IV, each character has his or her own Lunar Trial. Rosa's trial focuses on using her White Magic abilities to heal injured people, culminating in a battle with Lunar Asura.
Rosa's Pray, Aim and White Magic return with the same attributes as in Final Fantasy IV. She joins the party at level 30 with all the spells she would normally learn up to that point, including Teleport, and will learn new spells at the same levels as in Final Fantasy IV. She comes equipped with a Healing Staff, Sage's Miter, Sage's Surplice, and Rune Armlet.
Rosa has fairly good HP, the highest of the dedicated mage-type characters, and her Aim ability and decent Strength let her be a respectable attacker. Compared to fellow White Magic users Porom and Leonora, Rosa has greater HP, Strength and Stamina but lower MP and slightly lower Spirit than Porom, and all-around greater stats than Leonora.