AFAIK, the Japanese pronounciation would be straight up Rah-gah-rah-jah, with no particular stress on any of the syllables.

(It's not actually a Japanese word, but the original Sanskrit name of Aizen Myoo, the Buddhist "Wisdom King" responsible for transforming lust into transcendent joy and enlightenment. I have no idea what the original Sanskrit pronounciation should be... but then, I doubt any of the Ragaraja's patrons do, either. *g*)