Declension table of ?tatastya

Neuter	Singular	Dual	Plural
Nominative	tatastyam	tatastye	tatastyāni
Vocative	tatastya	tatastye	tatastyāni
Accusative	tatastyam	tatastye	tatastyāni
Instrumental	tatastyena	tatastyābhyām	tatastyaiḥ
Dative	tatastyāya	tatastyābhyām	tatastyebhyaḥ
Ablative	tatastyāt	tatastyābhyām	tatastyebhyaḥ
Genitive	tatastyasya	tatastyayoḥ	tatastyānām
Locative	tatastye	tatastyayoḥ	tatastyeṣu

Compound tatastya -

Adverb -tatastyam -tatastyāt