Declension table of ?tejasya

Masculine	Singular	Dual	Plural
Nominative	tejasyaḥ	tejasyau	tejasyāḥ
Vocative	tejasya	tejasyau	tejasyāḥ
Accusative	tejasyam	tejasyau	tejasyān
Instrumental	tejasyena	tejasyābhyām	tejasyaiḥ tejasyebhiḥ
Dative	tejasyāya	tejasyābhyām	tejasyebhyaḥ
Ablative	tejasyāt	tejasyābhyām	tejasyebhyaḥ
Genitive	tejasyasya	tejasyayoḥ	tejasyānām
Locative	tejasye	tejasyayoḥ	tejasyeṣu

Compound tejasya -

Adverb -tejasyam -tejasyāt