The monster guy up top would be Trixie's adopted father.He has the power to erase peoples memories but to do it to one specific person he has to touch them.He's the reason no one in the world remembers humans after they went extinct in the war.Hes killed by the main bad guy whom he used to work for(pictured below) shortly after giving Trixie a map to a safe city, and when she gets there her memories of her adopted father are erased