Matsunaga Hisahide, historically the lord of Yamato during Japan's Sengoku period, overthrew his master and died by suicide, detonating gunpowder-filled teapots in defiance against Oda Nobunaga. Reincarnated in modern times as a Chihuahua, he retains memories of his past life. His small canine form exhibits constant, uncontrollable shivering. Despite this instability, he demonstrates unexpected vocal talent as a skilled singer with a strong affinity for rock music.

His personality combines insanity with perverse tendencies; he exploits his diminutive size to gain physical advantages with female humans, often competing in this behavior with Takeda Shingen. This rivalry stems from their shared inclination toward voyeurism. While his mental state remains erratic, his engagement with modern music and social interactions indicates an adaptation to contemporary life, albeit through a distorted lens.

---
*Preserved all original details while enhancing narrative flow and conciseness.*