From Exalted - Unofficial Wiki
Roiye is perhaps the single most dangerous demon of his kind to the mighty. It is given to him that the more powerful and divine a heavenly creature is, the less visible he becomes in its eyes. A human sees him as much as any other demon might, as a twist of black threads, specks, and shadows, pitch as night. To the dragon-blooded, he appears as a flickering shade, still visible, but difficult to trace the movements of. A celestial Exalt can make him out dimly, if he stands still, as a minor dimming shaped into a man. To the agents of heaven, and the Solar Exalts themselves, he is invisible, untracable, and silent.
He may grant this selfsame invisibility to his lessers, and to whatever he is commanded to so imbue. While so affected, such a thing is beyond the reach of heaven, and while the Pattern Spiders still weave its fate, they are incapable of predicting the paths it takes, leaving a haze of tangled webs, and only in retrospect do things become clear.
For this reason, those things particularly bound to fate particularly dislike him, and when his handiwork turns up, it is common for the Bureau of Destiny to send Sidereals (and the Wyld Hunt, were applicable) to clean things up QUICKLY.