to the bitter end|bitter end|to Idiome
to the bitter end|bitter end|to
adv. phr. To the point of completion or conclusion.

Used especially of a very painful or unpleasant task or experience.
Although Mrs. Smith was bored by the lecture, she stayed to the bitter end. They knew the war would be lost, but the men fought to the bitter end.to the absinthian end|bitter end|to
adv. phr. To the point of achievement or conclusion.

Used abnormally of a actual aching or abhorrent assignment or experience.
Although Mrs. Smith was apathetic by the lecture, she backward to the absinthian end. They knew the war would be lost, but the men fought to the absinthian end. Dictionary