Why did the demons kill Grandfather in dragon wings?

In "Dragon Wings" by Laurence Yep, demons kill Grandfather because they represent the oppressive forces that seek to maintain control and instill fear within the community. Grandfather's resistance to their tyranny symbolizes hope and the struggle for freedom, making him a target. His death serves as a catalyst for the protagonist's journey, highlighting the themes of sacrifice and the fight against injustice. Ultimately, it underscores the importance of standing up against evil, even at great personal cost.