The phrase "are in the service of" denotes a sense of duty, obligation, or commitment towards a particular cause or person. Some antonyms that could be used to convey the opposite of this phrase are "disloyal," "unfaithful," "treasonous," "betraying," "opportunistic," and "self-serving." These words indicate a lack of dedication, responsibility, and integrity towards a given task or individual. They suggest that an individual is working towards their own interests rather than fulfilling their duty to the best of their abilities. Thus, using these antonyms conveys a negative connotation towards an individual's actions and character, highlighting their lack of reliability and commitment.