9S, or YoRHa No.9 Type S, is a scanner model android in NieR: Automata, serving in the YoRHa unit to combat machine lifeforms. Unlike combat-focused models like 2B, his role emphasizes reconnaissance, hacking, and data analysis, making him highly intelligent and inquisitive. Paired with 2B as her scanner support, 9S develops deep emotions and curiosity about the world, machines, and humanity. His journey reveals a shift from naive optimism to despair as he uncovers harsh truths about the war and YoRHa's secrets. Playful yet obsessive, he hacks into enemy networks and questions existence, forming a tragic bond with 2B across multiple playthroughs and endings.