I will explain using some kanji, so excuse me if your computer doesn't have East Asian character set.
In 1990, Chousedaigun (超世代軍 = Inter-Generation Army) was formed by some of the young wrestlers of All Japan: Misawa, Kawada, Taue, Kobashi, Tsuyoshi Kikuchi, and Satoru Asako. It was to start a inter-generational feud against the already-established top guys such as Jumbo Tsuruta, Stan Hansen, etc.
Right after the formation, Taue jumped to Tsuruta's Seikigun (正規軍 = Regular/Main Army).
After Tsuruta was hospitalized and stepped down from the main eventer spot, Kawada left Chousedaigun to team with Taue. Around this time, it was impossible to determine which team (Misawa's Chousedaigun or Kawada's) was the Seikigun (Regular/Main Army). However, they decided to call Kawada's team Seikigun anyway, but this time they made it up with a different combination of kanji: 聖鬼軍 (聖 = holy; 鬼 = oni). Thus, "Holy Demon Army" in English translation.
Jun Akiyama replaced Kawada in Chousedaigun in '93. With the guys like Kobashi and Akiyama becoming main eventers, Chousedaigun was dissolved in '98.
I'm not sure about the exact timeline since I got these years from some Japanese websites (including Wikipedia, whose Japanese section is usually more accurate than its English couterpart).