Learn Farsi: هیچ‌کس گنج مخفی مثل این مجموعه نداشت. - Nobody had a hidden treasure like this collection.

The verb داشتن (to have) is a special exception in Farsi. When it means possession, it doesn't take the می prefix for the continuous aspect. So نداشت acts as both "did not have" and "was not having" depending on the context of the story.

The word هیچ‌کس means "nobody", so why is the verb نداشت (did not have) also negative?

Farsi requires double negatives! Whenever you use a "zero quantity" word like هیچ‌کس (nobody) or هیچ‌چیز (nothing), the verb must also be negative. You are literally saying "Nobody didn't have."

Where do we need to add the invisible link (ezafe) when reading this sentence?

Two important hidden "e" sounds to notice are in گنجِ مخفی (ganj-e makhfi), which links the noun "treasure" to its adjective "hidden", and in مثلِ این (mesl-e in), which links the preposition "like" to its object "this".

Why is the verb نداشت separated from the rest of the sentence all the way at the end?

This is the standard word order in Farsi! The verb almost always goes at the very end of the sentence. The structure here is perfectly regular: Subject (هیچ‌کس) + Object (گنج مخفی مثل این مجموعه) + Verb (نداشت).