Kailus: Absolutely Borri

Kailus laughs, "It is not my ability but me size that I am considering. I look about the size of these northmen, while you do not. They see your shape and the game will be up."

As Borri leaves, Kailus helps to cover the unconscious man's body at the back to make it look as if it is sleeping. A quick check to make sure that he is still unconscious if warranted here.
The other two must be well hidden., There were only three men after all, replaces by the unconscious man, himself and Tain. A fourth body would cause suspicion.
He takes one of the cloaks, wraps it around himself and pulls the hood over his head, trying to look as much like a northman as possible in order to await the arrival of the others.