A contemporary and former friend of the Sannin, Hiruko wished to become a strong shinobi, yet was born with no natural special abilities. To overcome this disadvantage he developed the Chimera Technique, which would allow him to absorb the chakra of other ninja, as well as any Kekkei Genkai they may possess. Some time after the Third Great Shinobi World War, Hiruko divulged his findings on the technique and left the village as a missing-nin.
Dozens of years later, ninja possessing Kekkei Genkai begin disappearing from Kumogakure, Iwagakure, Kirigakure, and Sunagakure, leaving Konohagakure as the suspect and prompting rumors that they are preparing to rebel against the Land of Fire. While on a mission flying over Mount Shami, Sai falls under attack from a mysterious, bird-like monster. Team Kakashi soon arrives to rescue him, but encounter wolf-like monsters, and Naruto is injured in the struggle to escape. When Konoha ANBU are dispatched to investigate, they encounter Hiruko and his followers, Ichi, Ni, and San. Hiruko reassures his followers that there's nothing to worry about, then quickly dispatches the ANBU squad with his Chimera Technique, absorbing their Earth-nature chakra and using it manipulate the mountain itself, crushing them.
With the other nations amassing troops on the borders of the Land of Fire and threatening to invade, Hiruko uses a genjutsu to project his image in the skies over Konoha and deliver a message, announcing that he intends to obtain the Kekkei Genkai of the Land of Fire, becoming immortal and virtually invincible. With the combined power of Kekkei Genkai from all Five Great Nations, he plans to instigate a Fourth Great Shinobi World War and rule the world. In order to carry out this goal, Hiruko has been biding his time so that he can draw power from the Sun's corona during a solar eclipse, which is now rapidly approaching.