Roberto de Souza was born on September 19, 1989, in São Paulo, Brazil. Immersed in a family with deep martial arts roots, he began his journey under the tutelage of his father, Adilson de Souza, training alongside his brothers Mauricio and Marcos. Roberto's initial exposure to martial arts came through judo, which laid the groundwork for his transition to Brazilian Jiu-Jitsu as a child. Growing up in this disciplined environment, he absorbed the collective knowledge and unwavering commitment of his family, a foundation that proved instrumental in shaping his technical base and competitive mindset.

Roberto's path took a pivotal turn after his brother Mauricio established an academy in Japan. A visit to compete and reconnect with family inspired Roberto to relocate, embracing new challenges both on and off the mats. He balanced factory work with his ambitions in martial arts, steadily building his reputation as both a competitor and instructor. Co-founding Bonsai Jiu-Jitsu in Shizuoka, Roberto emerged as a cornerstone of the local grappling scene. As a coach, he has developed high-level athletes and fostered a culture of technical excellence, all while maintaining an active presence in Brazilian Jiu-Jitsu and mixed martial arts competition.

On May 1, 2011, Roberto achieved a defining moment in his career, receiving his black belt from his father, Adilson de Souza. This milestone carried profound significance, as his father passed away only hours after the promotion. Roberto continues to honor his family's legacy, upholding the principles and techniques instilled by his father throughout his journey in Brazilian Jiu-Jitsu.

Roberto de Souza etched his name in history as RIZIN FF’s first lightweight champion, submitting Tofiq Musayev with a triangle choke in June 2021. He showcased his finishing prowess with submission victories over Yusuke Yaji and Johnny Case, reinforcing his reputation for decisive grappling. In subsequent title defenses, Roberto submitted Luiz Gustavo and Yoshinori Horie—the latter via standing rear-naked choke in the first round at RIZIN 51 (2025). His MMA career is distinguished by a high submission rate and rapid finishes, a testament to his elite jiu-jitsu pedigree. As of August 2025, Roberto holds the RIZIN FF lightweight world title and has expressed interest in a potential transition to the UFC under specific conditions.

Roberto is recognized for his tactical adaptation of classic Brazilian Jiu-Jitsu guard work and triangle attacks to the demands of MMA. His precise timing and relentless pursuit of submissions define his approach, both in the gi and in mixed martial arts. Roberto seamlessly blends traditional BJJ fundamentals with a modern, pragmatic strategy, consistently leveraging his grappling expertise to control and finish opponents in high-level competition.