The fan service isn't a random hot spring scene. It's a contractual exchange. Kyouka must reward Yuuki to maintain his combat effectiveness. This shifts the dynamic from "gratuitous" to "functional."
From a production standpoint, Seven Arcs (the animation studio) is well-versed in this genre, having previously worked on titles like Senran Kagura and Valkyrie Drive . In Chained Soldier , the action choreography is designed to highlight the female form during combat. The "Slave" transformations are visual spectacles that emphasize the synergy between the commander and the pawn, often resulting in combat scenes that are a blend of high-octane violence and suggestive imagery. Chained Soldier Fan Service
The significance of fan service in "Chained Soldier" or any other work can be multifaceted: The fan service isn't a random hot spring scene
The series' most unique fan service device is the system. This shifts the dynamic from "gratuitous" to "functional
This trope is commonly found in genres such as ecchi (a genre of anime and manga aimed towards a male audience that often features fanservice), harem (a genre where a protagonist is surrounded by multiple potential romantic partners), and sometimes in more specific sub-genres like "Shotacon" (a genre focusing on romantic or sexual relationships between an adult and a younger male). The context can vary widely, from comedic situations to more serious narratives.