Ran'ji > WoD + Oracle of Light + Scorn!?

[Riastrad]

^ Above mentality discredits the untold number of years/generations he fought against the Sin-Eaters, training those Minfilia's and seeing them cut down, time and time again. This wasn't some rando who saw Vauthry and immediately bent the knee - this is a chap who was likely Numero Uno in the Sin-Eater slaying department on the First who had nothing to show for almost a century of fighting but constant defeat (or as close to it as you can get without being wiped out). Then Emet comes along, instigates the birth of a human Sin Eater who can control those beasties. You'd be tired too after all that time and far more susceptible to the notion that maybe throwing your lot in with that obese scumbag would be preferable to fighting for the losing side which now also has people defecting/mind-controlled and bleeding out numbers without even fighting at all. If not for himself, then for the other Minfilia's.

If the best you can do is die without putting up a fight and submitting yourself to a tyrant along with every other soul you know, then you may as well stop fighting all together. He didn't do that. He actively stood in the way of people trying to make a difference and was putting down people willing to, at the very least, try to fight for a world for their children. Call it for what it is. If you give it your all till it becomes too much, only to turn on those still fighting, that is the definition of being a traitor. And traitors should get what they deserve. What help he gave when Minfilia was actively trying to save the First was washed away when he decided that what he wanted was more important than her mission (saving the First). If a cutscene was added that at least made him falter in his current belief that the world was beyond saving, maybe I would have received his character better. As it stands he was just an annoyance and generally lackluster when it comes to being a well developed antagonist. He was only a stepping stone to our salvation of the First when he could have been an ally. He got off easy.