User blog comment:IamJakuhoRaikoben/Chapter 420: Lamia Scale's Thanksgiving, Review./@comment-24546844-20150216154609/@comment-24546844-20150217015719

In truth Gray is the one I think is most likelly to not join the guild again. Maybe then he will show up again only when the situation call for him. And with this I mean Natsu is possessed by E.N.D..

Other than him I can only think about Alzack and Biska denying the ofer to live a normal life with Asuka.