the bloodless ones

They are the experts in the field of holograms - able to somehow control the biggest outbursts of glitches - and sometimes cause them.

Despite that, they hunt down Saints to feast on their 'flesh' - supposedly to absorb their powers.
There also was at least one confrontation between the Bloodless Ones and the Vampires - but it might be just a chance encounter. 

'The reality was mortally wounded by the Old Corporations during the Final War. That's when they used the 'glitch bomb'. They thought that it would just destroy the Artificial Minds of their opponents - but in fact it tore a hole in reality. And we all know what crept though that wound.'

- N7D9H13313

The sect's name come from the fact that their leaders had supposedly ditched 'the constraints of mortal ichor' and glitched their flesh to replace their blood with 'holographic ectoplasm'.