Important figures in a setting should have a name, of course. Even more, many should have an epithet, a descriptive word or phrase that illustrates some element of the figure. When an epithet is distinctive enough and specific enough, it can take the place of the name itself in common usage.
In fact, during development I prefer to work with epithets, only assigning names when I need them. n my 13th Age-Style Icons in the Sandbox series, all thirteen identified icons are listed and discussed using only their epithets: Giant’s Daughter, Mountain King, Nature’s Heart, Queen Underhill, Storm Crone, First Bard, Hound, Unthroned King, Exemplar, Windmistress, Lord Seacrest, Radiant Lady, and the High One. During development I find the epithets more evocative and that they help me keep the nature of the figure in mind.
Epithets in real life are chosen to reflect some aspect of the entity being described. ‘Richard the Lion-Hearted’ was called that because of his bravery and boldness. The epithets used in the Icons series mentioned above were chosen this way, and I think this will generally be the most common method when choosing epithets for known entities.
For unknown entities, I’m developing a series of tables that will give me epithets I can use to guide development of the entity. Given just the name Barakhareesh, I would have been at a loss… but once I knew he was Dragon of the Seas I had a much better handle on him. Chalekan, Dreamer in the Pathways Below was the same.
… and looking at it, the tables would blow out this post. I’m going to leave them out, for now.