Potential nicknames: Atreyu can be nicknamed Trey or Tru.
Origin: German, through the use of the fictional native language in the novel it came from, meaning "son of all." The meaning came to be so because Atreyu's parents were killed by a buffalo soon after he was born and his village raised him.
Popularity: In 2010 there were 130 baby boys named Atreyu (about 2.6 per state) which does not rank on the Social Security Administration's top 1000 baby names in the U.S. In 2011 there were 5 spelled Atreu, 8 Atrayu, and 125 Atreyu. If you think it's weird, keep in mind there were 91 Anakin's in 2011. Atreyu is currently the most searched for name leading readers to this blog.
Fun fact: You will probably remember "The NeverEnding Story," Michael Ende's German novel and the 1980s movie series, in which one of the main characters is named Atreyu. If the book or movie does not instantly come to mind, you might be more familiar with the rock band Atreyu, formed in 1998, named after Atreyu from "The NeverEnding Story." These are the only two well known associations. Chances are no one born after 1995 will know where this name came from unless their parents intentionally introduce it to them. It will work well with other rare literary (but still legitimate,) name options coming about lately, such as Aramis and Merrick.