That's very intriguing and far from how I know them. While it's unlikely they'll perish from sunlight alone, the Vampires of Myddvai will lose their immortality if they linger too long beneath the sun's magic. [he hums, considering how different both those are from Dazai's ongoing vampiric transformation]

Different still from here, where they cannot be beneath the sun at all. Curious, the differences in details, but similarities in titles.