The Skully Islands are a large island chain located in the Spring Sea off the southwest coast of Usea, due south of Axel Bay and southwest of Seals Bridge. As of the late 20th century, the Skully Islands were under the jurisdiction of the Federation of Central Usea.
Skully Islands insurrection
In 1995, the islands' government was overthrown by terrorist forces. In response, Robert Tyler, the newly appointed commander of the FCU's Southern District military, was ordered to put down the uprising and restore order. The mercenary Scarface Squadron was subsequently hired to bolster the FCU military, confront the terrorist forces, and return the Skully Islands to Federation control.
Usean coup d'état
On July 7, 1998, during Usea's continent-wide coup d'état, Scarface Squadron was tasked with destroying the rebels' Usean 2nd Fleet, which was in the vicinity of the Skully Islands. During the operation, Scarface encountered the fleet's Cocoon Squadron, and a dogfight erupted over the ocean. During the skirmish, a new aircraft was detected on radar—another Zone of Endless (ZOE) unit. Taking advantage of this opportunity, Cocoon Squadron temporarily retreated while Scarface engaged the ZOE aircraft. After the ZOE unit retreated due to battle damage, Cocoon Squadron reengaged Scarface Squadron, which shot down all of the rebel fighters and emerged victorious. The operation was ultimately another success for the Usean Allied Forces.
- On the official Ace Combat 04: Shattered Skies website, a mistranslation of Japanese material led to the Skully Islands being referred to as "Scali" by fans. The error in translation was made apparent by the localized release of Ace Combat: Assault Horizon Legacy.