Shadowmancy

The Dwellers in Shade, or Shadowmancers, are a small and secretive ascetic order of Blooded mages, who believe that their discipline can be used to slow the progress of corruption while still making use of the power that it grants.

Because magic, and Blood power, are to some extent metaphysical in nature, and malleable by will, the Shadowmancers believe that the danger of the Blood is at least in part because of the way people think of it. They attempt to change this in part by changing the metaphor for its use.

As I've noted before, the Parable of the Poisoned Well is so widely spread that it is how most people - even most mages and magical scholars - think of magic and Blood.  The Shadowmancers believe that this metaphysical construct has become so widespread that it is effectively real, and they seek to change it. They instead believe that the corruption of the Blood of the Gods, as it is a phenomenal (if deadly) power source, should be thought of as the ultimate source of visible power - a sun. They attempt to focus their minds and wills to imagine the Blood in their systems as a small metaphysical sun, radiating its power and corruption outwards, rather than something internal that spreads outwards. They will then create what amounts to a shield of magical shadow to block the rays of this malevolent sun. Instead of manipulating the light from the Blood sun to create magic, they manipulate its shadow, using the negative metaphysical space to manipulate their environment in ways similar to those of standard mages.

This is all of course metaphor, and metaphysical construct. They are not physically creating a ball of light and a shield. Its essentially a use of creative visualization that manipulates the metaphysical realm in which magic has its physical stuff, rather than an actual physical creation.

Interestingly, the Dwellers in the Shade do seem to have something. On average, those Blooded who master their visualization exercises, and who can manipulate their own minds to fully set and accept the proper metaphors, do on average seem to be able to hold out against Corruption longer than most, and can seemingly hold off the decision between destruction and Blessing for years longer than most others.  Whether this is simply because the most studied ascetics possess the greatest willpower, or because of some material benefit of the discipline itself, is an open question.