Sōta Serizawa assists researcher Youko Nakaizumi, supporting her investigations into advanced technology and phenomena surrounding the Vox Units and the Rin-ne. His given name combines "sudden, sound of the wind" (颯) and "thick, big" (太), while his surname means "celery" (芹) and "marsh" (沢). In Season 2, he continues collaborating with Youko to analyze the Vox systems and the Rin-ne's mechanisms. Sōta frequently blushes and stutters in Youko's presence, revealing his romantic feelings for her. This emotional dynamic remains persistent alongside his primary focus on professional dedication.