Declension table of ?kṛṣṇārcis

Masculine	Singular	Dual	Plural
Nominative	kṛṣṇārciḥ	kṛṣṇārciṣau	kṛṣṇārciṣaḥ
Vocative	kṛṣṇārciḥ	kṛṣṇārciṣau	kṛṣṇārciṣaḥ
Accusative	kṛṣṇārciṣam	kṛṣṇārciṣau	kṛṣṇārciṣaḥ
Instrumental	kṛṣṇārciṣā	kṛṣṇārcirbhyām	kṛṣṇārcirbhiḥ
Dative	kṛṣṇārciṣe	kṛṣṇārcirbhyām	kṛṣṇārcirbhyaḥ
Ablative	kṛṣṇārciṣaḥ	kṛṣṇārcirbhyām	kṛṣṇārcirbhyaḥ
Genitive	kṛṣṇārciṣaḥ	kṛṣṇārciṣoḥ	kṛṣṇārciṣām
Locative	kṛṣṇārciṣi	kṛṣṇārciṣoḥ	kṛṣṇārciḥṣu

Compound kṛṣṇārcis -

Adverb -kṛṣṇārcis