Declension table of mantrin

Masculine	Singular	Dual	Plural
Nominative	mantrī	mantriṇau	mantriṇaḥ
Vocative	mantrin	mantriṇau	mantriṇaḥ
Accusative	mantriṇam	mantriṇau	mantriṇaḥ
Instrumental	mantriṇā	mantribhyām	mantribhiḥ
Dative	mantriṇe	mantribhyām	mantribhyaḥ
Ablative	mantriṇaḥ	mantribhyām	mantribhyaḥ
Genitive	mantriṇaḥ	mantriṇoḥ	mantriṇām
Locative	mantriṇi	mantriṇoḥ	mantriṣu

Compound mantri -

Adverb -mantri