"A Bookman walks through the world," the old man says, "his feet always steady on the line between light and dark."
The boy turns the little hammer over in his hands. He does not appear to be listening.
"A Bookman--" The man pauses. "Are you listening, boy?"
The boy waves his hammer in acknowledgment. "Yeah, yeah, go on!" He tosses the hammer up and catches it in the other hand. This makes him grin.
The old man sighs. "A Bookman does not take sides unless it serves his purpose to do so. To prevent his heart from betraying his purpose, he erases the parts of him that aren't a Bookman, and he gives a new name to the pieces that are left."
At this, the boy actually looks up. For once, he seems interested. "Does this mean I get to pick my own name?"
"Yes. Choose wisely."
The boy doesn't hesitate, doesn't miss a beat. "I wanna be Hammer Dude! No, Sir Hammer Dude!"
Silence. The old man looks down at him.
The newly christened Sir Hammer Dude hesitates for a moment, cheerful hope slowly dribbling out of his face. "...no?"
"How about Rabi?"
you know that's how it happened