What does that line imply? Seemingly nothing, besides for the following:

a) He existed
b) He was a human
c) He was tall

In terms of setting him as a character it:

a) Links him to the group of all human men, which can mean differing things to differing readers.

Consider the sentence with slightly different wording:

He was a short man.
[This case short is more stressed]

He was a man.
[This case man is the main emphasis]

He was a monster.
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Now, remembering the subtle connentations, consider how the following sentences work as irony:

He was a monster, always ready to give charity.

He was a man, always working on a new recipe.

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Through subtle statements like those, your story picks up instrinisc meanings.
Make sure to use them well.