Denroku Sukegawa, 73, is the janitor and boiler maintenance manager at Kissuisō hot spring inn. Having served since the inn's establishment, he holds the record as the longest-serving employee besides the owner himself. His responsibilities encompass building upkeep and managing the inn's daily operations journal. Staff members know him by the nickname "Beanman" or "Mameji," a playful reference to his previous employment at a bean factory.

Physically, Denroku possesses grey or white hair featuring distinctive twin ahoge strands and is frequently portrayed with closed eyes. He typically dons practical work attire suited for maintenance duties.

Though naturally reserved and speaking sparingly, Denroku remains highly observant, often detecting when fellow staff face troubles. On these occasions, he offers concise advice. His decades of service at Kissuisō have cultivated a close, respectful bond with the owner, Sui Shijima; he ranks among the very few who converse with her openly, and she values his counsel.

His primary domain is the boiler room, yet he routinely handles diverse minor tasks beyond the regular staff's duties, aiding the inn's overall upkeep. This deep institutional knowledge and quiet dedication solidify Denroku Sukegawa as a stabilizing presence within Kissuisō.