Adjectives (first, final, latest) can follow the verb "to be" without "the":
You are first. (first is an adjective)
You can go first (first used as an adverb modifying "go")
This is final (final is an adjective)
That is last (last is an adjective)
That is the last (last is a noun)
All of these are grammatical:
That is latest. ("latest" is an adjective). OK
That is the latest. ("latest" is a noun). Better.
That is latest information. ("latest is adjective, "information" is noun") OK
That is the latest information. ("latest is adjective, "information" is noun". Better.
As you see, many common words have multiple identities as nouns, adjectives, and even adverbs. "Last" is a good example of a word that can do just about anything. It is even a verb!