To me, this part of the book looks like Hemalurgy. Sadeas’ men accept the thrill, and as a result they open their spirit webs up to the control of Odium. Odium can then confuse their weakened minds, looking for combat, to attack the other Alethi.
I think the path the fuzed (and spren) take from shadesmar is Odium’s perpendicularity, riding on the Everstorm. Like how Honor’s perpendicularity rides the Highstorm infusing spheres as it passes. Radiant spren use Honor’s. Before the Everstorm was summoned, the listeners could only change form during Highstorm.