There are legends of a feline from medieval times that seem to tell a similar story to that of Zuriel's. That's what some people think, anyway. A legend of a large, warm-coated cat leading a rebellion against the corrupt ruler, who would stop at nothing, it seemed, to free those still under the king's grasp. While it's easy to draw parallels, there are some who take it too far, stating that Zuriel in fact is the feline in these legends.
It's a ridiculous theory to most, seeing as the feline written about is one of the first four Elemental Cores- all of whom were born centuries ago. Instead, the more accepted theory is that Zuriel s a direct descendant of the Flame Core, which would explain his ability to wield such a powerful strain of the Element.

The other legend that theorists tend to draw parallels to, however, is far more grim. That of Hell's Core. A tale of one of the first casters who stole an ability from the Powers, and later on stole the conductors of the first four in a search for total control. Because of this, it is also rumoured among these circles that that there are others, the ones who gifted the Cores with their abilities in the first place, who took mortal forms in a last-ditch effort to attempt to restore balance to the world.
Again, most people believe this to be a ridiculous theory, as Hell's Core was a made up story that parents would tell their children in hopes to keep them from becoming greedy with conductors and prevent Corrosion.

As such, Zuriel's personal history remains largely... Unaccepted, by the general public. Fine by him. He doesn't need anyone prying into where he got his rings.