That is how that noun declines.
Nominative singular: Azantys
Nominative plural: Azantyssy
Accusative singular: Azanti
Accusative plural: Azantī
To make it more confusing just as any natural language, there are other words/situations where the word can be the same for multiple meanings, for example "Hontī" is the accusative plural and the accusative singular so with that word as an object you will only know the number by context.