Thistle-Chaser is a character from a series of books called The Named (Ratha's Creature, Clan Ground, Ratha and Thistle-Chaser, and Ratha's Challenge). The series is set in a prehistoric world; there are no humans, large felines are the dominant species, and a few cats have evolved far enough mentally to have an awareness of themselves. This is demonstrated by their naming of themselves (the "Named") as opposed to wild, "normal" cats (the "Unnamed"). The Named cats herd animals, have fire, etc. They're also vastly outnumbered by the Unnamed, which leads to interesting conflicts and situations.
A few years ago, I wrote to the author (she lives in my state! Just a few miles away from me!) to see if she intended to write more in the series. Unfortunately she said she was not. However, I today found www.RathasCourage.com! (Apparently the site only works in IE, and as author-made sites sometimes are, it's a little rough around the edges.) The next book is coming out this year! Yay!
Anyway, back to my name. While Ratha is the main figure of the book, the name didn't have enough character for me to want to use it. I didn't like the Thistle-Chaser character much, but I loved that name. I figured that by using Thistle-Chaser people would make the connection to the book series, and that was good enough. (Those who remember it, anyway. The first book was published in 1983 and the last one in 1992!)
While I didn't like the Thistle-Chaser character much, there was one element about her that sort of matched me and so the name further fit. In the book, she got that name because she wouldn't learn (her mother was Named but her father was Unnamed -- pairings like that usually resulted in kits lacking "light in their eyes" -- an awareness of self). Again and again, young Thistle-Chaser would pounce thistles, never seeming to learn that pouncing prickly things hurts. I tend to not give up on painful things soon enough, too -- I often keep beating my head against a wall long after other people have stopped.
I've been using Thistle-Chaser as my online name for a good ten or so years now. It no longer feels like a name from a book, it just feels like me. :) And for FFXI people: Originally I was going to create myself as ThistleChaser, but was told that a shorter name was better, in case people had to type out my name for spells and such, so I shortened it to just Thistle.
I'm not going to tag 10 other folks. Do this or not, as you wish! :)
Edit: Link to the book on Amazon, for those who want it. And check out all the new cover art for the old books! Looks like they're releasing them all again.