An AI adversary red team configured to pentest email and/or network defenses implemented by a cyber threat defense system used to protect an organization and all its entities. AI model(s) trained with machine learning on contextual knowledge of the organization and configured to identify data points from the contextual knowledge including language-based data, email/network connectivity and behavior pattern data, and historic knowledgebase data. The trained AI models cooperate with an AI classifier in producing specific organization-based classifiers for the AI classifier. A phishing email generator generates automated phishing emails to pentest the defense systems, where the phishing email generator cooperates with the AI models to customize the automated phishing emails based on the identified data points of the organization and its entities. The customized phishing emails are then used to initiate one or more specific attacks on one or more specific users associated with the organization and its entities.