Which character points a sword at the shepherd's forehead?

points a curved sword at Santiago's head on the night they first meet.

The
Alchemist rides in on a large black horse in a cloud of dust. Santiago can't even see him until
the dust clears. He's wearing a turban, his face is mostly covered by a black mask, and he has a
falcon on his shoulder. He draws his sword, points it at Santiago, and then presses the tip of
the blade into his forehead until it draws blood.

He asks...