Io Hokari

Io Hokari is the former Bottle King and father of Ryou Hokari. He is the president of the Bottleman Management Association (BMA). His father is Suezou Hokari, the founder of BMA.

His name comes from Pocari Sweat, a Japanese brand of sports drink, and its Pocari Sweat Ion Water product.

(Source: Bottleman Wiki)