Declension table of ?śivamantra

Masculine	Singular	Dual	Plural
Nominative	śivamantraḥ	śivamantrau	śivamantrāḥ
Vocative	śivamantra	śivamantrau	śivamantrāḥ
Accusative	śivamantram	śivamantrau	śivamantrān
Instrumental	śivamantreṇa	śivamantrābhyām	śivamantraiḥ śivamantrebhiḥ
Dative	śivamantrāya	śivamantrābhyām	śivamantrebhyaḥ
Ablative	śivamantrāt	śivamantrābhyām	śivamantrebhyaḥ
Genitive	śivamantrasya	śivamantrayoḥ	śivamantrāṇām
Locative	śivamantre	śivamantrayoḥ	śivamantreṣu

Compound śivamantra -

Adverb -śivamantram -śivamantrāt