Roméo Conbolt, the only son of Fairy Tail mage Macao Conbolt, eventually becomes a mage of the same guild himself. As a child, he has straight, dark purple hair with prominent bangs covering part of his forehead, large eyes, and a small, mildly round nose. After a seven-year time skip, his appearance changes significantly; his hair grows longer and spikier, and he develops prominent abdominal and pectoral muscles, along with slight biceps. The Fairy Tail guild stamp is visible on his left shoulder. His attire evolves to resemble Natsu Dragneel's, consisting of a long, dark, sleeveless open jacket with lighter-colored edges, loose light-colored pants below the knees, low dark laced boots, a light scarf with a wavy motif tied in a front knot, and bandages wrapped around his forearms.

In childhood, Roméo is a kind and good-hearted individual who holds deep affection for his father and takes great pride in his profession as a mage, a feeling that fuels his own dream of becoming a mage. He exhibits significant admiration for Natsu Dragneel, viewing him as an older brother figure. The disappearance and presumed deaths of Natsu and the Tenrou team following the events on Tenrou Island precipitate a profound change in his personality. He becomes sullen, cynical, and critical of his father, whom he perceives as a coward for not defending the guild's honor during its decline. This period lasts seven years, during which he does not smile until the missing mages return.

As a full mage of Fairy Tail, Roméo transforms into a proud and dedicated member who actively defends the guild's name and honor against any insults. He addresses older guild members with the honorifics "Nii" or "Nee" and refers to Wendy Marvell as "Wendy-chan." His personality is generally cool, serious, mature, and clever for his age, exhibiting a stubborn refusal to back down from tough fights—a trait influenced by Natsu. Despite a somber exterior, he remains fundamentally friendly, valiant, and caring, willing to help others in need. He typically exercises more caution than his more reckless guildmates. He shows particular politeness and respect towards female guild members, a trait that distinguishes him and even allows him to bathe with them in hot springs, though he remains deeply shy and flustered around women, concealing his internal urges. He also demonstrates a fondness for animals, caring for and raising them, such as his direwolf Raksha, with whom he shares a strong bond.

Roméo's primary magical ability is Fire Magic, specifically a variation called Purple Flare, which allows him to create and manipulate purple flames resistant to wind and water. He manifests these flames from his arms or hands for attacks, binding opponents, or providing support. His spells include Purple Net, which ensnares groups with ropes or nets of purple fire, and Purple Bombardment, which generates explosive balls of purple fire. He later develops a more advanced form called Rainbow Fire, producing flames of different colors with unique properties: Blue Fire emits cold, Green Fire has healing properties, Orange Fire immobilizes targets, Yellow Fire produces a strange smell, and Red Fire creates a damaging stream and explosion. The culmination, Rainbow Fire, combines all colors into a single, powerful explosive flame.

Beyond magic, Roméo is an adept hand-to-hand combatant, employing a fighting style similar to Natsu's and often enhancing his physical strikes with fire. He demonstrates enhanced strength, speed, reflexes, endurance, and durability, capable of shattering walls, lifting objects twice his weight, dodging high-speed projectiles, and withstanding significant impacts. His magical power is considerable for his age, marked by a violet color, positioning him as a potential future candidate for the S-Class.

Roméo's story begins in childhood within Fairy Tail, where he fervently wishes to become a mage like his father. He urges Macao to undertake a dangerous job on Hakobe Mountain to slay Vulcans and impress bullies mocking his father's profession. When Macao fails to return after a week, Roméo seeks help from Guild Master Makarov, who initially refuses. Natsu Dragneel intervenes, rescuing Macao and strengthening Roméo's admiration. He participates in guild activities and events, covering for Natsu during the Eisenwald arc and witnessing the body-swapping incident caused by Changeling magic in the Phantom Lord arc, further solidifying his desire to be a mage.

The seven-year absence of the Tenrou team impacts Roméo deeply. He joins Fairy Tail during this period and is often seen gazing at the sea, hopeful for their return. He confronts guild detractors like Thibault and his crew, attempting to fight them with Purple Flare before being saved by the unexpected return of the missing mages. Their return brings him immense joy and his first smile in seven years. In the Key of the Starry Sky arc, Roméo participates in guild activities, including dance practices with Kinana and attempts to solve Lucy Heartfilia's invisibility problem. He takes part in the festival celebrating the showdown between Natsu and Laxus and engages in battles against antagonists like Coco.

Roméo shares a strong bond with his father, Macao, though it becomes strained during the seven-year gap before eventually mending. His admiration for Natsu Dragneel significantly influences his attire and fighting style. He develops romantic feelings for Wendy Marvell, though he often acts dense and brushes off pointed interest from guildmates regarding these feelings. He maintains friendly relationships with other guild members, including Lucy Heartfilia, Erza Scarlet, and Happy.