Beni is a pivotal character in Tenkai Knights, distinguished as the first female Tenkai Knight who possesses the core of the formerly evil warrior, Venetta. She is a thirteen-year-old girl with a striking appearance, characterized by her long pink hair that reaches past her waist and is often styled into twin tails, and her sleepy-looking turquoise eyes. Her typical outfit consists of a small, light lime green neckerchief, a black fitted top with red suspenders, a dark red headband, a pair of white-belted magenta shorts, and orchid boots.

Beni's background is marked by a deep-seated trauma linked to the planet Quarton. Her childhood was profoundly affected by her father's failure in his endeavors related to Quarton, an event that ruined her early years and instilled in her a desire for destruction. This history left her feeling isolated and mistrustful, believing that the only reliable path was to operate alone. Her personality is complex and evolves significantly throughout the series. Initially, she is portrayed as curious, highly inquisitive, and deeply arrogant, particularly regarding her perceived intellectual superiority over boys. She frequently makes dismissive comments about how "typical" boys behave, believing she can easily charm or outsmart them to gather information.

Beni's motivations are rooted in self-preservation and a cynical rejection of emotional bonds. She is a free agent who adamantly proclaims she is on no one's side but her own, viewing friendship as a burden that ties people down and inevitably leads to betrayal. This philosophy drives her to manipulate others, including the main protagonist Guren and her former partner Gen, to achieve her goals, which initially include locating the powerful Black Dragon Key. Her role in the story is that of a rogue and antagonist, shifting allegiances between the heroes, the villain Vilius, and her own personal agenda. She first appears in the episode "Lost Key" and later, as Venetta, she attacks Corekai soldiers on Quarton and battles the Tenkai Knights. In "Tenkai Rogue," she disguises herself as a helpless girl on Earth to get close to Guren and assess him. Her loyalties remain ambiguous for a long time; she seemingly betrays Gen and works with Vilius to find the Tenkai Fortress, only for it to be revealed that she was manipulating both sides to secure the Black Dragon Key for herself.

Key relationships define her journey. Her dynamic with Gen is significant, as they were once partners before she went rogue. She has a complex connection with Guren Nash, whom she initially tricks but later develops a grudging respect and even a subtle affection for, with Guren showing a willingness to accept her friendship. Ceylan Jones is particularly wary of her, often referring to her dismissively as "Pinky". The most transformative relationship in her development is with a young girl named Kiiro, Chooki's cousin. After meeting Kiiro, Beni's cynical views on friendship begin to change, leading to her eventual redemption.

Beni's character development sees her transition from a major antagonist to an eventual ally. Her turning point occurs in the episode "Heart Turns to Stone," where her interaction with Kiiro softens her resolve. She ultimately gives Kiiro the Tenkai Stone, a precious item left to her by her father, symbolizing her change of heart. By the end of the first season, she joins the Tenkai Knights, helping them in their final battles against Vilius. As a notable ability, Beni can transform into her Tenkai Knight form, Venetta. In this form, she is a formidable fighter known for her speed and agility, often using web-based attacks to restrain her opponents.