Declension table of mantrasiddhyupāya

Masculine	Singular	Dual	Plural
Nominative	mantrasiddhyupāyaḥ	mantrasiddhyupāyau	mantrasiddhyupāyāḥ
Vocative	mantrasiddhyupāya	mantrasiddhyupāyau	mantrasiddhyupāyāḥ
Accusative	mantrasiddhyupāyam	mantrasiddhyupāyau	mantrasiddhyupāyān
Instrumental	mantrasiddhyupāyena	mantrasiddhyupāyābhyām	mantrasiddhyupāyaiḥ mantrasiddhyupāyebhiḥ
Dative	mantrasiddhyupāyāya	mantrasiddhyupāyābhyām	mantrasiddhyupāyebhyaḥ
Ablative	mantrasiddhyupāyāt	mantrasiddhyupāyābhyām	mantrasiddhyupāyebhyaḥ
Genitive	mantrasiddhyupāyasya	mantrasiddhyupāyayoḥ	mantrasiddhyupāyānām
Locative	mantrasiddhyupāye	mantrasiddhyupāyayoḥ	mantrasiddhyupāyeṣu

Compound mantrasiddhyupāya -

Adverb -mantrasiddhyupāyam -mantrasiddhyupāyāt