Moonspear obscura

✴Revui doesn't notice the annoyance playing across his elder brother's face, but he wouldn't likely care even if he did. He is rarely sitting still and rarer still, willing to sit and listen to words. He is patient but his patience is hair-thin, but he doesn't have to wait too long before Jarilo succumbs and begins explaining things. He points out a cluster of stars and rambles about their father—but the image of this sky-creature, this massive snake encircling the world, slithers in to place in Revui's imagination. He wonders what it would be like to be up there, and remains silent and watchful of the sky.

When the silence goes on a touch too long he grunts, garnering his brother's attention, and glances at him with a curious expression on his face—stars brightly reflected in his gaze. What's it called?