Declension table of ?prastheya

Neuter	Singular	Dual	Plural
Nominative	prastheyam	prastheye	prastheyāni
Vocative	prastheya	prastheye	prastheyāni
Accusative	prastheyam	prastheye	prastheyāni
Instrumental	prastheyena	prastheyābhyām	prastheyaiḥ
Dative	prastheyāya	prastheyābhyām	prastheyebhyaḥ
Ablative	prastheyāt	prastheyābhyām	prastheyebhyaḥ
Genitive	prastheyasya	prastheyayoḥ	prastheyānām
Locative	prastheye	prastheyayoḥ	prastheyeṣu

Compound prastheya -

Adverb -prastheyam -prastheyāt