Declension table of ?kṛṣṇamitra

Masculine	Singular	Dual	Plural
Nominative	kṛṣṇamitraḥ	kṛṣṇamitrau	kṛṣṇamitrāḥ
Vocative	kṛṣṇamitra	kṛṣṇamitrau	kṛṣṇamitrāḥ
Accusative	kṛṣṇamitram	kṛṣṇamitrau	kṛṣṇamitrān
Instrumental	kṛṣṇamitreṇa	kṛṣṇamitrābhyām	kṛṣṇamitraiḥ kṛṣṇamitrebhiḥ
Dative	kṛṣṇamitrāya	kṛṣṇamitrābhyām	kṛṣṇamitrebhyaḥ
Ablative	kṛṣṇamitrāt	kṛṣṇamitrābhyām	kṛṣṇamitrebhyaḥ
Genitive	kṛṣṇamitrasya	kṛṣṇamitrayoḥ	kṛṣṇamitrāṇām
Locative	kṛṣṇamitre	kṛṣṇamitrayoḥ	kṛṣṇamitreṣu

Compound kṛṣṇamitra -

Adverb -kṛṣṇamitram -kṛṣṇamitrāt