Well I had considered the possibility that Yuuno might be of the Saint Kaiser lineage (based on his resemblance to Vivio). That might just add squick to it, I suppose.
In Daemon Kaiser, the original idea was for Volvo to possess Yuuno. However later on I considered the idea that Yuuno was indeed dead, but Volvo just looks like him because he's Yuuno's ancestor. That would have certainly worked as a better twist since everyone was expecting Yuuno to be alive but of course that would mean that Yuuno... well, wouldn't be alive