अथवा or else, स्वयम् by himself, कृतान्तः god of death, तव your, विनाशाय for destruction, अप्रतितर्किताम् inconceivable recourse, मायाम् conceit, विधाय right knowledge, रामरूपेण in the form of Rama, आगतः would have come.

"Or else, the god of death would have come in the form of Rama for your destruction, having right knowledge and taking an inconceivable recourse.