A more esoteric kind of magic

[Slimy_Slider]

Personally, I'm with the theory that so far, what we see the Fused using is not Voidbinding, but surgebinding hacked to use voidlight. Nothing the Fused do shows any difference from radiant abilities, except in the type of fuel, and something described as an entirely different system should probably be, well, different. The closest we see is likely Renarin and his corrupted spren bond, so the extent of this system is still highly unknown.