Samurai keeps children and online communities safe by detecting and responding to cyberviolence, sexual predators, suicidality and crisis - before the damage is done. Built on advanced AI that combines deep neural networks with symbolic reasoning, Samurai understands different types of cyberviolence well enough to intervene autonomously. By engaging directly in conversations to diffuse escalating aggression, and blocking violent content and users before they reach their intended victims, Samurai lowers cyberviolence by 50%, while reducing moderator load and cultivating healthy dialog.