Magister Templi

At the end of the Declare Battle Formations step, select one Thousand Sons Battle Trait (this can be a Rubricae Battle Trait, even though this model does not have that keyword, but it must otherwise be a Battle Trait this model can have and cannot be a Battle Trait this model, or the unit it is attached to, already has). Until the end of the battle, this models (and any unit it is attached to) is considered to have that Battle Trait.