This paper presents the concepts, issues on development, and future perspectives of a novel musculoskeletal humanoid `Kotaro'. The specifications and advantages of Kotaro include muscle-driven endoskeletal structure, multiple degrees of freedom, variable physical softness, the multiple-joint spine, easily configurable muscles, distributed onbody controllers, various sorts of many sensors including eyes, ears, and whole-body tactile sensors, and so on. These characteristics would achieve a flexible body, litheness of motions, safety, and adaptability and applicability to diverse tasks which would very often appear in human's daily lives