The Black Omen regiment was was founded by Rasalhague nobles, to support the Free Rasalhague Republic independence war against the Draconis Combine. Each company of the regiment was personaly commanded by a Rasalhague noble who also financed the unit. In result most Black Omen companies consisted of two platoons of mechanised infantry supporting a lance of Mechs.
Only a few companies survived the ronin wars and became famous under their own name as mercenaries. The Black Omen regiment ceased to exist after the clan invasion together with the Free Rasalhague Republic.