Then.

White City was the very same city Leonel had dropped from the sky to crush Anared and the Variant Invalid. Truth be told, he had only just remembered that he had traded the Ruby Imperial Pendant he had earned for it. He thought it might be a convenient way to get things started. After all, he didn't have the patience to build a new city even though he was uniquely suited to doing such a thing. 

As for what Leonel wanted the city for, it would be a convenient fort. Plus, he still had the enormous spatial Force Art he could repair and use again. Before he could only use it once before it got too damaged. But,  he was more than confident in making it even sturdier now. Though, it would take an even more powerful formation to move about in a Fifth Dimensional world.