Librarian in Terminator Armour

Before the battle, in the Muster Armies step, for each leader and support unit in your army, you can select one friendly bodyguard unit that unit can lead. That unit will then lead that bodyguard unit for the battle and form an attached unit with it. Unless otherwise stated, each bodyguard unit can only have one leader unit and one support unit attached to it.

If your Army Faction is **^^Adeptus Astartes^^**, at the start of your Command phase, select one unit from your opponent’s army. Until the start of your next Command phase, that enemy unit is your Oath of Moment target. Each time a model with this ability makes an attack that targets your Oath of Moment target:
■ You can reroll the Hit roll
■ If you are using a Codex: Space Marines Detachment and your army does not include one or more units with the **^^Blood Angels^^**, **^^Dark Angels^^**, **^^Deathwatch^^** or **^^Space Wolves^^** keywords, add 1 to the Wound roll as well.

Each time this unit makes an **ingress move** (20.04), if every model in this unit has this ability, it can be set up anywhere on the battlefield that is more than 8" horizontally from all enemy units, even if that is within your opponent’s deployment zone.