Jaime Alcaraz is a prominent character introduced during the events of Cardfight!! Vanguard G GIRS Crisis. He is a young professional cardfighter of Spanish origin who serves as a representative of the European League, often referred to as the Euro League's ace. At the time of his introduction, he is nineteen years old.

Jaime possesses a vibrant and extroverted personality, described as very outgoing and always eager to experience new things. His cheerful and sociable nature makes it easy for him to form friendships with a wide range of people. A distinctive aspect of his character is his frequent use of Spanish words and phrases when speaking, as Japanese is not his first language. He often calls others amigo, the Spanish word for friend. He has a noticeable flirtatious streak, which sometimes gets him into trouble, such as when his attempts at charm are met with sharp rebukes. His energy and positive attitude have earned him a considerable number of fans.

Beneath his playful exterior, Jaime is shown to possess a sharp intellect and a strong ability to read people. He can recognize hidden potential in others, such as when he identifies talent in a novice cardfighter or a rickshaw driver. His motivations are deeply rooted in his past. He grew up as an orphan in a children's home under the care of a man named Emilio. It was Emilio who gave him his first and most treasured card, One Who Surpasses the Storm, Thavas, and taught him how to play Vanguard. This card, which belongs to the Aqua Force clan, changed his life, and his bond with it is so profound that he once risked his own safety to retrieve it from a river. He views cardfights not just as competitions, but as a way for people to become amigos and form lasting bonds.

In the story, Jaime is invited to Japan by the Japanese Vanguard Association. He initially meets the protagonist, Chrono Shindou, under the guise of wanting a guide to learn more about Japanese Vanguard culture. During this tour, he demonstrates his clever and unorthodox methods, such as using souvenir candies to bait two quarreling boys into settling their dispute with a cardfight. This event reveals his philosophy that a shared battle can forge a strong friendship. His true identity as a top-tier fighter from Europe is eventually revealed to Chrono and his friends.

Jaime shares a key relationship with Chrono Shindou. He plays a significant role by providing Chrono with the crucial card Steam Maiden, Uluru, and later the Time Dragon, Nextage, tasks he performs on behalf of another character. He also spends time training with Chrono, helping him prepare for major tournaments. Beyond this mentorship, Jaime becomes a steadfast ally to the main cast. He competes in events like the Under 20 Championship and joins the fight against larger interdimensional threats, solidifying his role as a valuable member of the global cardfighting community.

Throughout the series, Jaime is shown to use the Aqua Force clan, which focuses on multi-attack strategies. His deck is built around his ace, Thavas, and he is a highly skilled fighter capable of competing at an international level. His tactical brilliance is often masked by his playful demeanor, but he consistently proves to be a formidable opponent whose abilities are respected by his peers.