Amazon X-Ray is a unique Kindle eBook feature that allows readers to learn more about characters and terms, simply by pressing on a word. Users can also enter a data repository and review all the book terms the author (me) has entered. This helps tremendously when reading a book series with an expanding list of definitions.

I've now added this feature to The Dauntless Disciple and The Conqueror's Nemesis.
Unfortunately, there are bugs in the web app for authors that forced me to repeatedly enter definitions.
However, I hope the result will provide an improved experience for ebook readers.