liberator       
noun [ C ] uk/ˈlɪb.ər.eɪ.tər/ us/ˈlɪb.ə.reɪ.t̬ɚ/
 解放者;拯救者
someone or something that helps a person or thing be free
  People came out into the streets to welcome the liberators. 人们走上街头欢迎他们的解放者。 
 The drug was hailed as a liberator of older women, promising to hold back the signs of ageing.  这种药物被誉为年长妇女的拯救者,有望阻止衰老的迹象。 
 See: liberate
 - More examples
 - The enemy soldiers were greeted as liberators by the peasants.
 - There are photographs of former death camp prisoners and their liberators.
 - She considers the hijab a liberator, which allows her to be judged on her mind, not her figure.