XXX-XD Directive

The XXX-XD Directive was an order issued by the United Nations Space Command to classify critical, important or otherwise urgent information or orders as restricted. It was used by the AI Endless Summer to classify United Nations Space Command Priority Transmission FLASH 91762P-06 when Zone 67 on Onyx came under attack in November 2552.

List of appearances

• Halo: Ghosts of Onyx (First appearance)