Declension table of ?kṛṣṇavastra

Masculine	Singular	Dual	Plural
Nominative	kṛṣṇavastraḥ	kṛṣṇavastrau	kṛṣṇavastrāḥ
Vocative	kṛṣṇavastra	kṛṣṇavastrau	kṛṣṇavastrāḥ
Accusative	kṛṣṇavastram	kṛṣṇavastrau	kṛṣṇavastrān
Instrumental	kṛṣṇavastreṇa	kṛṣṇavastrābhyām	kṛṣṇavastraiḥ kṛṣṇavastrebhiḥ
Dative	kṛṣṇavastrāya	kṛṣṇavastrābhyām	kṛṣṇavastrebhyaḥ
Ablative	kṛṣṇavastrāt	kṛṣṇavastrābhyām	kṛṣṇavastrebhyaḥ
Genitive	kṛṣṇavastrasya	kṛṣṇavastrayoḥ	kṛṣṇavastrāṇām
Locative	kṛṣṇavastre	kṛṣṇavastrayoḥ	kṛṣṇavastreṣu

Compound kṛṣṇavastra -

Adverb -kṛṣṇavastram -kṛṣṇavastrāt