Ramen no Yoroi-san operates the popular ramen shop "Rou" within the series' setting, distinguished by their striking golden armor and white bandana—attire evoking traditional Japanese culinary professionals. The establishment enforces an intricate ordering procedure requiring patrons to learn specific protocols beforehand. Individuals like Momonga who disregard these rules face immediate expulsion, demonstrating strict operational enforcement.

Shisa serves as their apprentice through the "Super Part-timer Program," developing professional skills under this mentorship. Shisa addresses the armored figure as "Master" with profound respect, aspiring to share a drink upon earning a liquor qualification. This dynamic anchors key narrative interactions.

Beyond work, Ramen no Yoroi-san maintains close bonds with fellow armored individuals Pochette no Yoroi-san and Rōdō no Yoroi-san. The trio frequently socializes through activities like shared picnics, reflecting camaraderie extending past occupational roles.

Though initially perceived as stern due to rigid policy enforcement and bluntness, underlying kindness surfaces through consistent mentorship of Shisa and positive peer interactions. Official media adaptations have not explored extensive background details or character development.