Yasaburo Manajiri is a masterless ninja drawn into Rangiku Fumiwatari's quest for vengeance against feudal lord Sadayoshi Karimata. He begins as a self-serving and sarcastic figure, motivated by personal gain and openly questioning the princess's motives while pointing out tactical flaws in her plans. Witnessing Rangiku's combat prowess and learning of her tragic past involving child flesh harvesting for puppetry shifts his mercenary attitude.

His combat expertise features heightened sensory perception for detecting danger and proficiency in ninja techniques, including illusion casting. During the final confrontation, he employs lifelike puppet illusions to deceive Sadayoshi, enabling Rangiku's strategic victory. This demonstrates his adaptability in battle coordination despite initial reluctance to join her mission.

Physically, he possesses distinctive long eyebrows and gray hair, often displaying exaggerated facial expressions during surprise or distress. His interactions with Rangiku reveal underlying moral complexity, such as when an attempted assault during her bath stops short upon confronting her innocence and trauma, highlighting a reluctant protective instinct beneath his cynical exterior.

Functionally, he serves as Rangiku's bodyguard during puppet operations, compensating for her vulnerability while controlling combat constructs. Their dynamic evolves from transactional cooperation to an unspoken alliance against shared enemies, though he maintains pragmatic skepticism throughout.