ultimately vs in the end

ultimately and in the end both are adverbs.

Word	Noun	Adjective	Verb	Adverb
ultimately	No	No	No	Yes
in the end	No	No	No	Yes

As adverbs, ultimately and in the end are synonyms defined as:

Other synonyms of ultimately include at last, at long last, finally.

ultimately (adverb)	in the end (adverb)
as the end result of a succession or process	as the end result of a succession or process
	eventually or after a lengthy period of time