Soga no Emishi
Soga no Emishi was the head of the powerful Soga clan, one of the five great uji, in the mid-7th century. He was a blood relation of the Imperial line through a maternal link, and oversaw the extermination of the Mononobe, making one of his sons the new head of that once powerful family group. He maneuvered to place Empress Kogyoku on the throne, and was considered to be the most powerful man of his time. Along with his son and heir, Soga no Iruka, he had built two moated manors, guarded by a subordinate clan. He was even able to award his son the right to wear a purple court cap--the highest court grade in the recent kan'i system--without Imperial sanction.
According to the Nihongi, his powerful position drew out his enemies, and he was eventually assassinated in the Isshi Incident of 645, when chief court ritualist Nakatomi no Kamako and Crown Prince Naka no Oe plotted the downfall of Soga power at court. Together they ambushed Soga no Iruka during a court audience with the Korean ambassadors, and Naka no Oe later came to Soga no Emishi's residence with other enemies of the Soga. The guards eventually fled, and Soga no Emishi was killed, though not before burning several critical documents, including possibly the first ever written history of Japan.