Nintendo President and Chief Executive Officer Satoru Iwata, 55, has died after spending the last year battling serious illness, according to a statement released by the Japanese gaming firm. Speculation surrounding Iwata’s health had been rife after he missed the 2014 E3 presentation and was imitated by a puppet during the same event this year.

"Nintendo Co., Ltd. deeply regrets to announce that President Satoru Iwata passed away on July 11, 2015, due to a bile duct growth", read a statement from the publisher.

Iwata had undergone surgery to have the growth removed last year. Through a Nintendo statement at the time, Iwata said that the growth “can be difficult to treat, partly because of the difficulty of detecting it early” but that he had been lucky.

He added, “I was counseled that removal at an early stage would be the desirable medical option. Therefore I had surgery last week, and I came through it well, as predicted.”

Iwata began working as a programmer at Nintendo’s HAL laboratory in the early 1980s, before moving up the ranks in the 90s. He became a director of the company in 2000 and was appointed president in May 2002. He oversaw the launch of the GameCube, the Nintendo DS, 3DS, Wii and Wii U, which represented some of the company’s most successful periods.

During his time at Nintendo, Iwata focused on transparency and open communication with his fans. He hosted the "Iwata Asks" series of game developer interviews, which helped pull back the curtain on the highly secretive company. He was admired for his friendly and care-free attitude.