Every noun has just as many forms. Which one gets used depends on which way the noun is used in a sentence. "Dāria" is the nominative version, which gets used for the subject of a sentence. "Dārie" is the accusative version, which gets used for the direct object of a sentence. "Dārio" is the genitive case, which translate to roughly "of the queen/the queen's". "Dāriot" is the dative case, which is used for the indirect object of a sentence. And then there's the locative (dāriā), the instrumentative (dārȳsa), the comitative (dārȳma) and the vocative (dārȳs) cases.
High Valyrian uses all those cases instead of lexical constructions like English does. It doesn't have words for "to" or "of" or "on" or "with". Instead it has cases, and the noun changes its form based on it.