Wizard Brother of Samular Caradoon
Renwick helped his brother, Samular Caradoon protect Summit Hall until he and his brother had a falling out and he left the keep. He never saw his brother again. After Samular passed, Renwick returned to Summit Hall for a time to help protect it once more.
Templeton suspects that the lich encountered in the Monastery of the Sacred Stone is in fact Renwick Caradoon. His theory was put to the test when he parlayed with the Lich and called him out as such. The parlay went well resulting in some magic item trade and help.