Can someone translate this uncommon name into Japanese?

Hi! I'm not foreign in Japanese, and I'm no expert at translating words into this language yet. I was wondering what the name, 'Lilithea', would become once translated into Japanese. I know 'Lilith' becomes 'Ririsu', but, I'm not sure how to go about on the 'thea' part of the name. Your help is much appreciated!!