Matter makes up practically everything on earth. However, this race just represents the individual particles that make up matter as we know it. This is a quite odd race, since it isn't really a race, but that's the best way to classify it currently.
Matter appears in "The Marvelous Molecular Masterpiece."
Way too much stuff to put here. Matter does pretty much EVERYTHING.
The two subraces of matter used in Epic Battle are Elements and Molecules. Elements are Elements, and Molecules are Molecules. I hope that clears everything up.