Doctor Facilier works as an ongoing villian. He's a deal maker so you could build him up that way. He's goes to other worlds and makes deals with the inhabitants. He helps them get what they want in exchange for....a favor, a plot coupon, their souls etc. Most of the new Disney villians aren't mustache twirlers like Maleficent's crew was. So them forced to help out Facilier is a good way to use them. It also gives them a reason to stick around. They help Yozora out of remorse or they get in too deep with Facilier and can't back out.
I have 2 ideas for a Yozora centric villian.
The first is based of Zaheer from Legend of Korra- a revolutionary with religious undertones. Yozora is basically Noctis so you could have this character go against the institution Yozora represents.
The other is based of Azula- the child of the villian whose goes after Yozora. They serve as an ongoing rival.
Both characters are followed by a group of friends who help them out. You could explore friendship/bonds in a different way than before.
I'm a writer so if I had to work on Verum Rex, these what I would pitch.