From Longman Business Dictionary
paymasterpay·mas·ter /ˈpeɪˌmɑːstə-ˌmæstər/ noun [countableC]1ACCOUNTINGJOBORGANIZATIONSa person or organization responsible for giving people their wages or the money they are owedPaychecks are routed to an employee through their department paymaster.
2journalism someone powerful who pays other people to do something illegal or dangerous for themcriminal paymasters