How come it looks like "rōvor" and "embri" are clashing with their cases? Am I missing something?
Embri is single accusative form of embar. Rōva is a class I adjective and takes the form of rōvor in the nominative and accusative for aquatic nouns. See more here https://wiki.dothraki.org/High_Valyrian_Adjectives#Class_I
To put it another way, some adjective inflections may match the noun inflections, but others won't. Rōva before lunar is rōva, giving rōva vala ; but rōva before aquatic is rōvor, giving rōvor embar (in the accusative, rōvor embri).
Good question! It basically depends on their gender class, as well as the case and if it's plural or not. So an adjective like "Big" could have 8 different endings - 4 depending on the class, 2 depending if it's plural or singular, and 2 if it's nominative or accusative - and that's if I counted it correctly.
And also the same thing happens with Possessives as well. That's why "My" keeps changing depending on what class the noun is, and whether it's plural or singular. There is a lot to learn in High Valyrian.
The infinitive form of the verb is: izūgagon
v. Obl. appl. [High Valyrian Verbal Prefixes: Oblique Applicative] C-fin. [High Valyrian Verb Tables: Consonant-final] to fear
Ñuhī zaldrīzī izūgilā. — You will fear my dragons.
From Dothraki Wiki: https://wiki.dothraki.org/High_Valyrian_Vocabulary