He's Strong
Northern and the stranger were a combo to boot.
As Northern displaced the monsters with his sword, he watched with one eye compartment to see if the stranger wasn't trying to do anything funny like attack him from behind.
Or perhaps, get smart with his clone and monster.
But the guy just continually fought the White Walkers.
His movements were swift and fluid, very swift and way better than any Northern had come across.
Raven, of course, would always be in a lane of her own. But this guy was a befitting comparison to her, though her speed didn't even come close.
In less than five minutes, they were done. Of course, the stranger was done first, but not less than thirty seconds later had Northern cut down the last of his foes.
He turned to the stranger who immediately asked him:
"So what next?"