Kenji Asuka serves as a key member and the designated leader of the Crasher Squad, Earth's elite space-defense force established to confront extraterrestrial threats. Holding the rank of captain, his primary function is to coordinate defensive operations and strategic missions, often piloting advanced combat vehicles and specialized mecha units into direct engagements with hostile forces. He works directly alongside the protagonist Takeru Myojin, known as Mars, as well as teammates Naoto Ijuin, Mika Hyuga, Akira Kiso, and Namida Akashi in their collective struggle against the Gishin Empire.

In terms of personality, Kenji demonstrates a notably protective attitude, particularly toward younger or more vulnerable members of the team such as Namida. This behavior is a reflection of his deep-seated sense of duty to safeguard both civilian populations and his fellow soldiers. His leadership style provides essential stability and support within the team dynamic, helping to maintain focus and morale during the high-stakes conflict.

Kenji's primary motivation throughout the narrative is the successful execution of the Crasher Squad's objectives, relentlessly prioritizing the collective safety of Earth and his comrades above all else. He maintains a critical cooperative relationship with Takeru during battles against the primary antagonist, Emperor Zuul, and his generals. Across all official media including the television series, the 1982 theatrical film, and the 1988 OVA, Kenji is consistently depicted as a courageous and committed soldier. His notable abilities include strategic combat coordination, piloting skills for both conventional and mecha-based weapon systems, and the tactical acumen required to lead a defense force against a superior imperial enemy.