Epsilon is a commercial product sold by Lugaru Software. It was first released in 1984, long before Emacs was available on personal computers, and modestly priced, so it provided an attractive alternative to the usual DOS editors for those accustomed to Emacs. It was also the first DOS based editor to allow editing of files that were larger than available RAM.
Epsilon supports Unicode but does not display characters outside the BMP and cannot presently handle right-to-left scripts. It can convert among dozens of character encodings.