Declension table of ?dvādaśāyus

Masculine	Singular	Dual	Plural
Nominative	dvādaśāyuḥ	dvādaśāyuṣau	dvādaśāyuṣaḥ
Vocative	dvādaśāyuḥ	dvādaśāyuṣau	dvādaśāyuṣaḥ
Accusative	dvādaśāyuṣam	dvādaśāyuṣau	dvādaśāyuṣaḥ
Instrumental	dvādaśāyuṣā	dvādaśāyurbhyām	dvādaśāyurbhiḥ
Dative	dvādaśāyuṣe	dvādaśāyurbhyām	dvādaśāyurbhyaḥ
Ablative	dvādaśāyuṣaḥ	dvādaśāyurbhyām	dvādaśāyurbhyaḥ
Genitive	dvādaśāyuṣaḥ	dvādaśāyuṣoḥ	dvādaśāyuṣām
Locative	dvādaśāyuṣi	dvādaśāyuṣoḥ	dvādaśāyuḥṣu

Compound dvādaśāyus -

Adverb -dvādaśāyus