I posted this on the support forum but maybe here is a better place. The Knights of Immolation have some color differences, like the purple feathers on their shoulders. And their armor is a slightly different shade. But it is hard to tell them apart from the regular Doom Knights in regular gameplay. I often find myself mixing them up with the normal unit in gameplay, and in MP I could see an opponent not being able to tell the two apart.
Changing them to a silver color scheme or just any color that would be different from the normal blue and gold would help a lot. And making their weapons actually flaming would help visualize their unit role at a glance without having to look at the item card for that detail. They are meant to have magical and flaming attacks, but the VFX are also a bit too subtle.
I know other RoRs have some issues looking pretty similar to the normal unit. But I just thought the Knights of Immolation were a particularly egregious example, and it's the first time it actually affected my gameplay.