Declension table of ?kaṣṭatva

Neuter	Singular	Dual	Plural
Nominative	kaṣṭatvam	kaṣṭatve	kaṣṭatvāni
Vocative	kaṣṭatva	kaṣṭatve	kaṣṭatvāni
Accusative	kaṣṭatvam	kaṣṭatve	kaṣṭatvāni
Instrumental	kaṣṭatvena	kaṣṭatvābhyām	kaṣṭatvaiḥ
Dative	kaṣṭatvāya	kaṣṭatvābhyām	kaṣṭatvebhyaḥ
Ablative	kaṣṭatvāt	kaṣṭatvābhyām	kaṣṭatvebhyaḥ
Genitive	kaṣṭatvasya	kaṣṭatvayoḥ	kaṣṭatvānām
Locative	kaṣṭatve	kaṣṭatvayoḥ	kaṣṭatveṣu

Compound kaṣṭatva -

Adverb -kaṣṭatvam -kaṣṭatvāt