Who is Howie from The Great and Secret Show: The First Book of the Art and what is their importance?

Howard (Howie) is Trudi's son. He returns to Palomo Grove to find out the truth about himself, as his mother never told him anything about his father. He falls in love with Jo-Beth immediately, incurring the jealousy of her brother. Howie is later asked by his father, Fletcher, to help him in the fight against the Jaff, but he wants no part in their fight. When Howie is attacked by the Jaff, he flees to his father, only to see Fletcher destroy himself in battle.