The IUN (full name unknown) is an international organization on Strangereal.
By 1996, the IUN was involved in peacekeeping efforts during a standoff between FCU and Erusean forces in Ugellas and Amber. However, the FCU forces retreated on April 20, 1996 following the Ulysses 1994XF04 announcement; their retreat forced the IUN to also retreat. The IUN's retreat was notably hampered by logistical difficulties and heavy storms, preventing their retreat from fully taking place until April 22.
Sometime following the Continental War, a group of Erusean rebels seized a military factory that was under the IUN's control. The rebels, calling themselves Free Erusea, launched attacks across the Usean continent. The Independent State Allied Forces launched Operation Katina to quell the rebellion.
- The IUN plays a similar role to the United Nations in the real world.
- The Neo United Nations also played a similar peacekeeping role. Since the IUN was introduced in Ace Combat 04 promotional material, it may have acted as a retcon for the Neo United Nations.