sentence makes sense?

Question

Then unwittingly left the world behind

does this sentence makes sense in terms of a natural death

Answer 1

You would need to add a subject to the sentence, such as then HE unwittingly left the world behind

Answer 2

This is an incomplete sentence, so you'd need to add a subject/noun. Who or what left the world behind? This subject or noun would go at the beginning of the sentence.

An example could be a sentence like this: Then the soul unwittingly left the world behind.