Tears to Tiara is a very interesting take on both the legend of the man who would become King Arthur AND Lucifer. Much of the story's elements and characters are also linked to ancient Welsh legends as indicated by Lucifer's common name of Arawn and his meeting of the elf king Pwyll thousands of years prior to the story's main events. The timing of the "present" events also seems to mesh with Arthurian legends that place his life around the time of the late-Roman era Britain (Albion in the series). Beyond that, much of the story involves fights with the "Divine Empire" (stand-in for Rome) and later against the White Spirits. The story between Lucifer/Arawn and the White Spirits is very intriguing as it totally recasts the image of Lucifer as a protagonist and hero as well as the reasons for his fall from Heaven and his holy war against the angels. Other interesting links to legend are the fact the series mostly takes place at Avalon castle (no Camelot) and real clans including the Gaels and Brigantes are heavily involved.
The action of the series is great with some spectacular sword fighting and a handful of magical elements. The music is both thrilling and touching. I have never played the video game the series is linked to, but this story is very entertaining.