- Official Fan-Submitted Content: The volumes always feature one or two fan-created elementals with explanation of their abilities, a small selection of fan art, and one or two two-page fan comics. The hardcover books (Mundo Elemental and Panda Ninja Fantasma) take this further, with a whole section for fan art, fan comics and fan fics. While this content is clearly non-canon, the author takes pains to make sure it doesn't and won't conflict with the story.
- Science Marches On: Or rather, science terminology marches on. In chapter 74, published March 2016, a character called Noctio, whose element is ununoctium, is introduced. Now, ununoctium is a real-life super-heavy element first synthesized in 2002. But "ununoctium" was always a temporary name for the element, and the final name of "oganesson" was given only eight months later, in November 2016.
Trivia / 5 Elementos