Jia Xu
Around 196, the warlord Zhang Xiu was based in Nanyang Commandery (南陽郡; around present-day Nanyang, Henan). Jia Xu secretly contacted Zhang Xiu and conveyed his intention to join him; Zhang Xiu agreed and sent his men to receive Jia Xu. Before Jia Xu left Duan Wei, someone asked him, "(Duan) Wei treated you generously. Why are you leaving?" Jia Xu replied, "(Duan) Wei is suspicious by nature and he's wary of me. Even though he treats me generously now, I believe he will harm me eventually. However, if I leave now, he will be more than happy to see me gone. If I manage to help him find an external ally, he will treat my family well. (Zhang) Xiu lacks a strategist, so he definitely hopes to have me on his side. By leaving, I can protect myself and my family."