Who is Harpocrates in the novel, The Tyrant’s Tomb?

Harpocrates - also known as the silent god - is a minor egyptian god who eventually became a greek god when humans started to believe in him in that way. Before the opening of the novel, Caligula overpowers and locks him away in a shipping crate on top of Sutro Tower, using his silence to drown out the communications of the demi-gods. Furthermore, Tarquin gives Harpocrates the jar containing the Sibyl’s voice - the only sound he’s heard in thousands of years. While the two bond over their shared hatred of Apollo, they also willingly give their lives to save Camp Jupiter, letting go of their resentment to find peace in the afterlife.