DetonatioN FocusMe founder Nobuyuki Umezaki, one of the pioneers of Japan’s professional esports industry, died on July 29, 2026. The organisation announced his passing on August 3. He was 43.

Umezaki founded DetonatioN in 2012 and spent more than a decade helping develop the organisation into one of the most recognisable names in Japanese esports.

One of the defining moments came in 2015, when DetonatioN introduced salaries for its FocusMe League of Legends players and established a gaming house. The move made FocusMe Japan’s first fully professional team built around that model and represented an important step in the development of esports as a career in the country.

DetonatioN FocusMe later became one of Japan’s most prominent international representatives in League of Legends. DFM made multiple World Championship appearances, with its landmark 2021 run making it the first LJL representative to advance from the Play-In into the main group stage at Worlds.

Following Umezaki’s death, GameWith president and CEO Takuya Imaizumi has taken over leadership responsibilities at DetonatioN.

No cause of death has been publicly disclosed. Umezaki’s wake and funeral were held on August 1 and 2, while his family has asked people to refrain from sending flowers, condolence money or gifts.

A decision on whether a separate public memorial ceremony will be held has not yet been announced.