Declension table of ?kṛṣṇavaktra

Masculine	Singular	Dual	Plural
Nominative	kṛṣṇavaktraḥ	kṛṣṇavaktrau	kṛṣṇavaktrāḥ
Vocative	kṛṣṇavaktra	kṛṣṇavaktrau	kṛṣṇavaktrāḥ
Accusative	kṛṣṇavaktram	kṛṣṇavaktrau	kṛṣṇavaktrān
Instrumental	kṛṣṇavaktreṇa	kṛṣṇavaktrābhyām	kṛṣṇavaktraiḥ kṛṣṇavaktrebhiḥ
Dative	kṛṣṇavaktrāya	kṛṣṇavaktrābhyām	kṛṣṇavaktrebhyaḥ
Ablative	kṛṣṇavaktrāt	kṛṣṇavaktrābhyām	kṛṣṇavaktrebhyaḥ
Genitive	kṛṣṇavaktrasya	kṛṣṇavaktrayoḥ	kṛṣṇavaktrāṇām
Locative	kṛṣṇavaktre	kṛṣṇavaktrayoḥ	kṛṣṇavaktreṣu

Compound kṛṣṇavaktra -

Adverb -kṛṣṇavaktram -kṛṣṇavaktrāt