Candela, a Romani girl from a traveling community that sometimes camps near the monastery, becomes Marcelino's steadfast companion. Her nomadic background brings her community into conflict with local figures like the Duke of Mosto, who threatens eviction when they settle on his land. Candela's grandmother, the old matron gypsy, possesses knowledge others misinterpret as witchcraft, fueling tensions after the Duke blames her for his pond drying up. Candela actively partners with Marcelino to investigate such incidents, demonstrating resourcefulness by discovering a beaver dam caused the water loss and helping devise a solution with animal allies.

Her role extends beyond supporting Marcelino's personal quest to find his mother; she acts as his investigative partner in community mysteries. She aids him in proving a traveling showman's guilt for village thefts by uncovering film reels that provide an alibi for their friend Ouro. During disputes with the Duke, Candela and her family take refuge in the monastery, showing her integration into Marcelino's world and acceptance by the monks. She participates in significant events, including accompanying Marcelino on a celestial journey where he learns about his origins and his mother's fate.

Candela develops growing confidence and leadership, confronting school challenges alongside Marcelino. She consistently displays loyalty, courage, and a practical nature, using her observational skills to navigate dangers and assist others. Her relationship with Marcelino evolves from friendship into a partnership where they jointly undertake missions to protect both animals and people.