Masca: The Beginning

Although this was released after the 12 volumes of Masca, it is a prequel to the main story. It shows how Caien became a demon lord, about his relationship with Rakin, The King of Speira, and the love triangle between the 2 with the beautiful Rea of the mascan race. Asarella also apears, but the story seems to be concentrating more on Rakin and Rea.

(Source: Evil Flowers)