In this guide for development team managers, addressing toxic senior employees is explored through a multifaceted approach. The manager is encouraged to identify toxic behaviors early, initiate open communication to understand motivations, and set clear expectations for behavior and performance. Constructive feedback, along with documentation of incidents, plays a crucial role, providing a basis for potential formal actions. Promoting team building, involving HR when necessary, and empowering the affected team members contribute to mitigating toxicity. Training and development opportunities for interpersonal skills are suggested, and ongoing evaluation ensures the effectiveness of implemented strategies. The goal is to foster a positive workplace culture that supports the team's success while addressing and rectifying toxic behaviors.