self-sacrificer

self- +‎ sacrificer or self-sacrifice +‎ -er

self-sacrificer (plural self-sacrificers)

1. A person who offers himself or herself as a sacrifice (as a religious act, for example).
   • 1668, Henry More, Divine Dialogues‎, London: James Flesher, Dialogue 3, page 467:

     […] they even willingly forfeit all the rest, and turn as it were Martyrs and Self-sacrificers to but so faint a Shadow or scant Resemblance of the first uncreated Perfection […]

   • 1728, attributed to Daniel Defoe, The Memoirs of an English Officer, London: E. Symon, p. 186,

     After these Street-Exercises, these ostentatious Castigations are over, these Self-sacrificers repair to the great Church, the bloodier the better; there they throw themselves, in a Condition too vile for the Eye of a Female, before the Image of the Virgin Mary […]

2. A person who is self-sacrificing, who sacrifices their own benefit for the good of another or others.
   • 1856, Amelia M. Murray, Letters from the United States, Cuba and Canada, New York: Putnam, Letter 23, pp. 281-282,

     Northern clergymen in Florida, Scotch ministers in the North, and bishops with dioceses each as large as all England; men devoted to religion, charity, and learning—self-sacrificers, fearless, incorruptible […]

   • 1906, Mark Twain, chapter 2, in What is Man?‎, New York, page 19:

     It was a state of joy which only the self-sacrificer knows.

   • 1985, Maryellen Walsh, chapter 6, in Schizophrenia: Straight Talk for Family and Friends‎, New York: Quill, page 129:

     […] I think self-sacrificers tend to burn out early; they haven’t taken care of themselves.