- "If it wasn't at least this hard, it wouldn't be a very interesting match."
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Roselle Mateus (ロゼル・マティウス Rozeru Matiusu?) is the second male to join the Rune Angel Troupe and the seventh member overall. Due to his superb piloting skills, he was selected to pilot the prototype mass-production Emblem Frame, the Holy Blood. He learned his piloting skills for the sake of his sister, Bianca, so he would be able to take her on a flight through space.
Even before officially joining the Luxiole's crew, Roselle wears the standard military uniform of the EDEN military that consists of black pants, white dress shirt, and a jacket. The jacket has black, white, and gold elements with a red communications device on the left side. Unlike Kazuya, Roselle wears a red tie while keeping his jacket buttoned down the middle and also wears it underneath his belt. He is also seen wearing a pair of white gloves.
Roselle and his sister Bianca were born on an unknown planet in the EDEN universe under the Transbaal Empire. Roselle and Bianca were close siblings and even when Bianca was bedridden with sickness, Roselle would be there for her. Bianca's dream was to fly through the stars which prompted Roselle to become a pilot to fulfill her wish. Roselle recounts the two spending one of her birthdays inside her hospital room in the period of his studies to become a pilot. When Roselle was finally admitted to become a pilot after being instructed by Noa, he arrived to the empty hospital room with Bianca having passed away during his absence. Roselle's reaction to his sister's death was not small as he was not able to do anything for a few weeks and ended up losing 40kg's.
Back in gear, Roselle disciplined himself and strictly limited his social interaction with others and trained for the sake of keeping his goal of being the top pilot of his institution. He eventually joined the ranks of the UPW with Noa.
Roselle is assigned as the new member of the Luxiole's Rune Angel Wing after the crews' change in leadership. With Tact becoming chief of UPW, he passed down the mantle to Coco and the new Luxiole crew, with Roselle and Tapio, are sent to survey NEUE once more.
In the battles against the Three Marquis, Roselle took the helm along with Kazuya and partook in all the operations in sabotaging the Three Marquis's plans. The two assisted Anise in navigating Azeat's asteroid fields to reach Calvados' flagship whilst running into Anise's band of acquaintances. Then they help Nano sneak through Benedictine's fleets in Femto to reactivate the defense satellites. Finally, the two join Tequila in investigating the magic barrier that Genievres put up on Magiic.
Depending on the route (and in half of them) Roselle will become a romantic rival to Kazuya. In Rico's route, Roselle's overall superiority in age, looks, and skills led Kazuya to think Rico would prefer Roselle over him. In Roselle's part, he became interested in Rico's smarts and thought he was better suited for her. In Kahlua's route, he questions Tequila's feelings for Kazuya and believes that Tequila is only faking love for Kazuya only to make Kahlua happy and he begins a relationship with strictly Tequila. In Anise's route, Roselle begins to partake in a multitude of Anise's competitive games and began to grow fond of her and declared that he was capable of becoming a better accomplice in her "treasure hunter" lifestyle than Kazuya was. In the other routes, Roselle would be a minor problem with the exception of Lily's route. In Nano's route, Roselle shares his backstory with Kazuya where Nano unintentionally overheard it and tried to cheer him up by taking the form of his sister, Bianca. Roselle spends more time with Nano in Bianca's form recounting his memories of her until Nano's memory begins to be replaced with Bianca's. In Natsume's route, Roselle objects against Kazuya's action in stopping the political marriage between Soldum Seldar and Natsume as he believes that what Natsume is doing is for the greater good. Only in Lily's route does Roselle help in repairing the relationship as he joins the rest of the team in making Lily decide between her love for Kazuya and her duty as a member of the knights of her planet.
Whatever the case may be, Roselle repaired his relationship with the team and Kazuya after he formally apologized for his actions. In all routes, he thanks Kazuya for teaching him the value of friendship and camaraderie and calls Kazuya "the better man" after the conflict concludes. While still calling Kazuya "naive" he thanks him for the change of atmosphere since he joined the team and his change in character since his days of strict training and practice. Roselle promises to take everyone to visit Bianca's grave together once their duties are over. Roselle sacrifices himself at end of the game when he releases the Chrono Strings from the engine of Holy Blood to kill Parfait.
Roselle is mentioned at the very beginning of the game where Kazuya and his chosen Angel visit Bianca's grave to speak of his brave actions that saved everyone. Roselle's pendant had somehow ended up on the chosen Angel's Emblem Frame and it is kept by Kazuya until the end of the game. By Chapter 9, it is revealed that Roselle was reconstructed and had been utilized by the Will. His body was restored by the Will's technology and his missing pendant caused him to experience immense despair that allowed for the Will leader, Herea, to take control of Roselle's physical body, granting it immense power. However, he returns to normal by the pendant's memories when Kazuya is called down to the Master Core in the final confrontation. While Kazuya seemingly "dies", Roselle gets himself and Kazuya's chosen Angel to safety and rejoins the crew on the Luxiole to lead the Rune Angel Wing in their penultimate fight against Will inside ABSOLUTE. Because of the shock of Kazuya's death lingering in the crew, the reactions to his return from the dead are lackluster. In all endings, he is seen talking to Kazuya right before his partner arrives.
- "It took me four years to get this level of skill, but I should have been able to get it in one"
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Similar to Chitose, Roselle is an exceptionally talented and skilled individual who was chosen for his incredible talents to become part of the Angel Wing. Whereas Kazuya was chosen by fate and had no previous military experience prior to his training, Roselle was trained since his earlier years to become a pilot and exhibits excellence in physique, mentality, and skill. Above all, Roselle placed priority into his sister's promise and strictly kept to himself to train and ever increase his already formidable skills in piloting. While this did not necessarily mean Roselle was anti-social, his determination for self-improvement left him with little to no friends.
When Roselle did make social contact, it can be difficult to even think that he had very few acquaintances given his politeness. Roselle values order and duty as he repeatedly turned down relaxing with the members of his team in favor of resting his body and exercising to keep himself in top shape to pilot his Emblem Frame. He also was understandably concerned with Tapio's presence and rank as he had a suspicious opinion on the Val-Fasq. Roselle's speech and demeanor gives off an air of confidence and capability thanks to the hard work and skills he acquired that got him this far. Roselle's perfectionist attitude touches upon his competitive nature and assertiveness that is highlighted in the route conflicts he is a part of. It also angers him greatly to fall short of his high expectations as he constantly strove for greater heights of skill.
Roselle's comedy is similar to Lily's in a sense that he is mostly serious and his inexperience with the Angel Wing's extremities leave him dumbfounded to witness their quirks. While Kazuya had around a few months to get used to his team's varying personalities, Roselle's previous avoidance of social contact left him at a disadvantage when it came to properly dealing with them. Nonetheless, Roselle got along very well with the Luxiole's crew and his skills were lauded by most who worked with him previously. Even more similarly to Lily, Roselle has his moments of sentimentality in the form of his late sister and understandably has her memory and wish close to his heart.
In nearly all routes (with the exception being Nano), Roselle finds attraction toward a certain trait in one of the Rune Angel Wing's members. In Rico's, he admires her intelligence and diligent work ethic. For Lily, while unspoken, he finds her discipline a positive trait. For Kahlua, he focused on Tequila and admired her assertiveness and maturity. In Anise, he found fulfillment through her competitive nature and raw skill. In Natsume's, he found her selflessness and responsibility noteworthy. While they started off as workmates, Roselle's relationship with Kazuya potentially has him become a romantic rival to the latter's established relationship. However, by the end of the conflict, Roselle rights his wrongs and apologizes to him. He found that even though the friendship might have gotten rocky at some point, he valued the lesson he and the rest of the team taught him in the worth of friendship.
- Roselle's name is derived from a juice made from the Roselle plant called Royal Roselle.
- Roselle is the only male character with a personal theme song.