Brother Librarian Artenius simply gave a drawn out sigh when he heard the two battle brothers begin to argue with each other. The Librarian was too occupied trying to figure out what actually occurred to even care about the two brothers  and their petty bickering. Gently picking up one of the Xenos firearms, he gave it a general look over to confirm that there was indeed no signs of battle nor damage upon its surfaces. The weapon's drab olive colouration was unblemished as a whole if anything it seemed factory new, even lacking any sort of paint chipping that was so common when stationed in the battlefield. 

Setting aside the gun, he remained kneeling for several seconds, reaching out into the warp to deliver a very clearly precise message into the minds of the Son of Russ and Dark Angel, it went as such: “Cease this petty squabble, at once.” With luck, neither of them would come to blows. Turning his mind from either of them, Artenius grabbed hold of a Tau uniform and looked over it, also ensuring that it held no battle damage upon its surface, which it did not as the surface was totally lacking in blemishes.

Roughly dropping the armour before him before standing himself up with some effort, the Librarian motioned for the kill-team to follow him into the depths of the Tau fortress, though it seemed as though they had other ideas. Given his chapter of origin, he repressed the emotions he felt towards the pair, their bickering was not impressive to the Librarian, but he wouldn't voice these concerns, not yet.