"Kastra embri vokti ossȳngis."

Translation: The blue seas terrify the priest.

[ThomasRami1]

Why this sentence is using the acusative "embri" like a plural instead "embra"?

[Xenon-]

The nominative plural is the same with accusative singular for nouns in -ar.

[ThomasRami1]

With "-ar" do you mean aquatic type nouns?