Kagami Hayato is a Japanese virtual YouTuber affiliated with Nijisanji, a large VTuber agency known for anime-styled streamers. Yoroshiku is a common Japanese expression used when meeting someone new, roughly meaning please treat me well or I look forward to working with you. Short greeting clips like this one circulate on soundboards because they are instantly recognisable, easy to drop into edits and useful for introductions. Fans keep using it as a compact, friendly hello that signals a VTuber-style opening without needing a longer voice line.