Otaku is a Japanese term commonly associated with fans of Japanese animation, comics or video games. Otaku culture has grown to be a global phenomenon with various hobbies and media. Despite its popularity, research efforts to contribute to the otaku culture have been modest. Therefore, we present Hatsuki, which is a humanoid robot that is especially designed to embody anime characters. Hatsuki advances the state of the art as it: 1) realizes aesthetics resembling anime characters, 2) implements 2D anime-like facial expression system, and 3) realizes anime-style behaviors and interactions. We explain Hatsuki's design specifics and its interaction domains as an autonomous robot and as a teleoperated humanoid avatar. We discuss our efforts under each interaction domain, and follow by discussing its potential deployment venues and applications. We highlight opportunities of interplay between otaku culture and interactive systems, potentially enabling highly desirable interactions and familiar system designs to users exposed to otaku culture.