Short answers, pulled from the story.
Dentsu serves as the unofficial communications department of the governing Liberal Democratic Party. This connection is so tight that the company has been likened to the CIA on account of its reach.
Japan Telegraphic Communication Co., Ltd. changed its name to Dentsu Inc. on the 1st of 1955. This name change marked a new era of corporate evolution that would see it grow into the largest advertising agency in Japan.
Matsuri Takahashi committed suicide in December 2015 after Dentsu was caught exceeding its own 70-hour monthly maximum overtime limit. The Japanese government recognized her death as karoshi, a Japanese term for death from overworking.
Dentsu agreed to acquire British-based Aegis Group plc on the 12th of July 2012 in a cash deal worth $4.9 billion. The deal was completed in March 2013, and Dentsu Aegis Network managed all Aegis Media work and non-Japanese Dentsu operations worldwide.
The Dentsu Building was designed by Jean Nouvel, the French architect, and completed in 2002. It is a high-rise building in Shiodome, Minato, Tokyo, which houses Dentsu's corporate offices.