Luca has black hair and violet eyes. His outfit is black with white detailing at the cuffs, with black-on-black detailing at the lapel. He wears white gloves, a black bowl tie, and a flat-top black hat with a white ribbon around it.
Luca is usually quiet, but reliable. As Felicità's attendant, Luca is entirely devoted to serving her. He being her attendant since she was a young child, he commits fully and willingly stay by her side. He is shown to be very protective of Felicità and addresses her as "Milady" or "Oujo-sama." He speaks in a sophisticated way and is mindful of manners, as well as other's manners, especially in the company of Felicità.
He is commonly shown in a comical light in the anime, with other members of the Arcana Famiglia teasing and pushing him aside. However, he has also been shown to have a more serious side, particularly when it comes to protecting Felicità.
For the most part, he seems to take pride and delight in being the perfect attendant, loyal to the family and always ready with whatever the social environment demands. He deals with stress by bottling it up and shying away from socializing. Despite this, he's always ready with a small treat or trick to cheer up others.
He took lessons as a child from Jolly on how to use alchemy, which he has become proficient in.
At one point, when Mondo went on an impromptu trip around the world to find love, Luca was put in charge of the entirety of Arcana Famiglia. The island's feudal lord and executives managed most of the work, and Catarina helped him, so he managed fine.
Luca has been Felicità's attendant since she was young because of his arcana power to cancel other powers. As her attendant, he was also her teacher in fighting and throwing knives.
Luca's first appearance in the anime was when Felicità was walking for patrol and Luca is later seen at the front door to Felicità's room. Luca is also seen at papa's birthday looming because Felicità is not wearing a dress.
He makes a variety of dishes over the series. In episode 2, he makes limonata. For Piccolino, Luca makes baci di dama. Specifically, he also makes tea, a bitter soup for sickness, and cannoli, but he and the maid trio appear to make the majority of the Arcana Family's meals.
In the Duello, Luca uses his arcana power to defeat a no-name minor Arcana family member in the first round. Then is soundly defeated by Felicità in the next round.
In the manga, Luca takes a much bigger position in the plot. He is crucial in keeping Felicità's Wheel of Fortune arcana from hurting her. When the time comes for her to use it on Mondo, Luca offers himself as a sacrifice instead of Felicità's memories. Gli Amanti accepts this.
In the Duello, Luca defeats Libertà in the first round. He goes on to defeat Jolly before facing Felicità. In the final round, he confesses his feelings. Unfortunately, he's not very clear about it, so Felicità doesn't fully understand until later when he explains himself properly.
Temperance Arcana (禁酒, Kinshu, La Temperanza) #14 of the Arcana Taroccos. The stigmata is located on his tongue. While activating it emits green light. Cursed, this Tarocco will take the contractor's voice.
- Il Bacio dell'Angelo (The Angel's Kiss): Luca uses this ability to neutralize the powers of other users of Arcana Cards. In the anime, he used it for the first time during Arcana Duello. In the manga, he uses it twice when Felicità uses the Wheel of Fortune arcana. He licks her skin to use it.
- Pigeon Magic: Luca can conjure pigeons (or doves since the Japanese character for dove and pigeon are the same) from his hat. He uses this tactic to distract Jolly during his duel in the visual novel.
- Alchemy: Jolly taught him alchemy, and Luca has continued to improve on his own. He can produce a variety of effects with this, such as making potions or fireworks.
- Felicità: His wife. Luca was Felicità's guardian when she was young in case she can't control her Arcana. He is her valet, and loves cooking and making tea for her. He often has trouble talking about love with her.
- Debito and Pace: Luca's childhood friends. He often talks with them and plans pranks on Jolly with them.
- Jolly: Alchemy teacher and father. Luca respects him as a superior alchemist, but not as a human or relative, and avoids him as much as possible. He, along with Pace and Debito, despise Jolly because he experimented on them to force contracts on Arcana Taroccos. He spikes Jolly's tea when he knows his father is going to drink it.
- Luca's voice actor, Clint Bickham, voices another character who shares the same birthday; Finland from Axis Powers Hetalia.
- Saint Luca is the patron saint of scientists and Luca is an alchemist.
- He is Felicità's primary love interest in the manga. This is not the case in the anime.
- Luca has the least brutal or humiliating repentance: making lemon pie.
- Luca's Arcana is Temperance, the virtue of moderation and self-restraint.
- Luca has been compared to a few characters from other series. Notably, this includes Dazai Osamu of Bungou Stray Dogs, Gilbert Nightray of Pandora Hearts, and Hotarou Oreki from the Hyouka series (interestingly, Luca's seiyuu, Yuichi Nakamura, also voiced Hotarou). These may be debatable, but this may just show that this is a memorable character archetype.