Inquisitor Eisenhorn

If every model in your army has the IMPERIUM keyword, you can include AGENTS OF THE IMPERIUM units in your army even if they do not have the Faction keyword you selected in the Select Army Faction step. The maximum number of AGENTS OF THE IMPERIUM units you can include in your army depends on the battle size

In addition, you cannot select a VINDICARE ASSASSIN, CULEXUS ASSASSIN, EVERSOR ASSASSIN or CALLIDUS ASSASSIN to be your WARLORD.

While a Bodyguard unit contains a Leader, it is known as an Attached unit and, with the exception of rules that are triggered when units are destroyed (pg 12), it is treated as a single unit for all rules purposes. Each time an attack targets an Attached unit, until the attacking unit has resolved all of its attacks, you must use the Toughness characteristic of the Bodyguard models in that unit, even if a Leader in that unit has a different Toughness characteristic. Each time an attack sucessfully wounds an Attached unit, that attack cannot be allocated to a Character model in that unit, even if that Character model has lost one or more wounds or has already had attacks allocated to it this phase. As soon as the last Bodyguard model in an Attached unit has been destroyed, any attacks made against that unit that have yet to be allocated can then be allocated to Character models in that unit.