reliever

Noun

• a pitcher who does not start the game

• a person who reduces the intensity (e.g., of fears) and calms and pacifies
  • a reliever of anxiety
    
  • an allayer of fears
    

• someone who takes the place of another (as when things get dangerous or difficult)
  • the star had a stand-in for dangerous scenes
    
  • we need extra employees for summer fill-ins
    

Related words

• Synonyms: 
  relief pitcher , fireman , allayer , comforter , stand-in , substitute , relief , backup , backup man , fill-in