Robella (known as RO635) is a rational and professional T-Doll with a strong sense of justice. She says she acts not only on orders, but also on responsibilities. Other Dolls noticed she has a unique "will" to get revenge against Sangvis Ferri for the destruction they caused. She also places great value in the given word. She tends to get flustered in situations unrelated to work or when things go wrong. Her optimism sometimes gets the better of her and leads her to make tactical mistakes.