Declension table of ?mahādevīya

Neuter	Singular	Dual	Plural
Nominative	mahādevīyam	mahādevīye	mahādevīyāni
Vocative	mahādevīya	mahādevīye	mahādevīyāni
Accusative	mahādevīyam	mahādevīye	mahādevīyāni
Instrumental	mahādevīyena	mahādevīyābhyām	mahādevīyaiḥ
Dative	mahādevīyāya	mahādevīyābhyām	mahādevīyebhyaḥ
Ablative	mahādevīyāt	mahādevīyābhyām	mahādevīyebhyaḥ
Genitive	mahādevīyasya	mahādevīyayoḥ	mahādevīyānām
Locative	mahādevīye	mahādevīyayoḥ	mahādevīyeṣu

Compound mahādevīya -

Adverb -mahādevīyam -mahādevīyāt