Who is Zampano from House of Leaves and what is their importance?

Zampano lives in the Lude's apartment complex. He is an older man, who enjoys spending his time feeding the birds. When Lude realizes he hasn't seen the old man in awhile, he calls the police, who find Zampano dead in his apartment. After Zampano's body is removed from the apartment, Lude comes across the papers that tell the story of the Navidsons.