noun. One who manumits or frees; an emancipator.

noun. An emancipator from slavery, someone who manumits.

noun. someone who frees others from bondage

"Consequently, we understand a gift of liberty to be avoided only when the creditors are defrauded both by the intention of the manumitter, and in fact: that is to say, by his property being insufficient to meet their claims."

manumission  manumissive  

liberator