Nishio

He is the only friend of Sakaguchi. Actually, he is more like his drinking buddy than anything else. He makes his living by scrapping coal off what is left from the town's abandon coal mine, where Sakaguchi would drop by to provide the muscle by pulling the mine cart and then selling the coal. Most of the day's earnings though ends up being spent in sake joints where he and Sakaguchi would wind up drunk and wasted.

Sakaguchi often calls him "Old Man" for reasons that he is actually old enough to be his grandfather, and yet he still acts immaturely. He later on followed Sakaguchi to Tokyo where he is under going sumo training at a local sumo stable, he now works in various odd jobs in order to earn a living, though at times he would watch Sakaguchi's matches.

(Source: ANN)