The Imperial Guardians once served the Imperial Empire until its demise by Deep Snow's betrayal and the elite unit became part of Demon Card under the same man who later become Oracion Seis' newest member because they had nothing better to do.
They later participated in Deep Snow's campaign to take out the Rave Warriors right after they're exhausted from the previous battle with Jegan and his dragon army. Although they were ambushed by a large Imperial remnant force, Underground, the group easily defeated them without much difficulty and then proceeded to kill the Rave Master and his friends.
The Imperial Guardians almost beat the Rave Warriors in battle partly due to their exhaustion, forcing Haru to call for a retreat. The unit then pursued the company until they encountered Shuda and battled the ex-Oracion Seis member but were all killed with the exception of Lazenby who was knocked out earlier and saved by Haru Glory to become their comic-relief ally, leaving him the only surviving member of the Imperial Guardians.