Mono.BW is emotionless, twisted and malicious. He’s obsessed with perfection, and views anything with color as "imperfect" and "ugly", having an irrational hatred of all things colorful, preferring to live in a monochrome world decimated by his hatred of colors. Mono.BW is also cold-blooded, ruthless and sadistic. He enjoys torturing the in-game characters and punishing them just for existing with colors. Mono.BW is presented as being calm and composed, and never oversteps into acting unhinged.