The advent of new technology has historically always lead, inevitably, to it's exploitation. No matter the intended purpose or the desire technology is always twisted by criminals to suit their own needs. New Republic civil defense and police forces knew this, and once they began incorporating things like powered armor, hard suits, and mecha they began preparing.
A special unit was formed under the direct control of the New Republic's police forces. Charged with being a rapid deployment strike force capable of engaging armored threats, be they personnel or mecha. Trained and equipped the Advanced Defense Unit, or ADU, quickly saw action throughout New Republic space on countless worlds combating situations local forces weren't equipped to handle.
Unfortunately as things deteriorated politically funding for the ADU was withdrawn, and requests for ADU interventions skyrocketed. Suddenly without support to maintain equipment and freedom from a political leash, the ADU turned autonomous. Declaring itself it's own independent faction the ADU began contracting itself to worlds and systems who could manage to pay their fees. The once proud arm of New Republic police forces, was now forced to become mere mercenaries. However, ADU discretion still determines where and when they act. No political or economical influence holds final sway over their involvement in any situation. Much to the dismay of criminals everywhere.
The standard ADU powered armor, the P-1a "Law-maker" has been in use for over 20 years due to it's robust frame and it's ability for long term deployment. Designed for patrol and general purpose duty Law-makers are equipped with personnel restraint and riot control in mind limiting their combat role.
As a counterpoint to the Law-maker the ADU developed the P-3e "Enforcer" a heavier armor equipped almost solely as a swat or heavy weapons capable frame. Armed with formidable weapons like Hybrid Type I pulse particle guns, riot grenade launchers and a pair of assault blaster to name a few the enforcer excels in most fire fights.
However without flexibility or endurance of it's predecessor the Enforcer didn't provide the ADU with a complete strategic package. For some time Enforcers were only brought to bear when needed and Law-makers were used to mop up and as support.
In an attempt to fill a gap in their tactical capabilities the ADU developed the P-2d "Inquisitor" powered armor for their detectives. The Inquisitor was designed to be a more armored Law-maker, with added equipment allowing detectives in the field to coordinate with other officers and have more intelligence on hand. With few on board weapons however detectives often had to rely on side arms and the tactical edge on board databases and intelligence could provide. To further give Inquisitors added flexibility and range internal thrust stabilizers were built into the armor allowing them better functionality in low and zero g environments and enhanced combat maneuvering short term.
Utilizing all three armor packages has allowed the ADU to adapt their squads to almost any situation or threat.