Stier Castle is an historic Belkan castle positioned on the southern edge of the border between Belka and North Osea (formerly South Belka) in the Waldreich Mountains, northwest of Sudentor. In modern times, Stier Castle would witness several important events that shaped the outcomes of the Belkan War and Circum-Pacific War.


Stier Castle is situated on the northern banks of Lake Edelwasser[2] and is surrounded by rolling hills and sparsely populated farmland. The castle is connected to a small rural town just north of the lake. Stier Castle stands on the southern point of an oblong promontory known as a drumlin, which provided protection against attacks from the lakeside. The keep is positioned atop two staggered tiers, and the castle's northern grounds are surrounded by tall defensive walls with watchtowers.

Stier Castle is one of many remnants of Belka's feudalistic heritage. Many of the legendary Belkan Knights were said to have spent time at Stier Castle during the heyday of the Belkan Empire.


Belkan War

Pixy flying by Stier

Pixy over Lake Edelwasser[2]; Stier Castle is visible in the background

Main article: Operation Ravage

On June 6, 1995, Stier Castle witnessed one of the seven nuclear detonations only a few dozen miles to the southwest. Despite being close to Ground Zero of the detonation, Stier Castle miraculously survived the blast.[3]

Main article: Operation Valkyrie

Several months later, on December 25, Stier Castle witnessed the destruction of the XB-0 Hresvelgr after the extremist group "A World With No Boundaries" used it to bomb Ustio's Valais Air Force Base. As the heavy command cruiser flew north towards Nord Belka, it was intercepted by the mercenary Galm Team northeast of the castle. Stier Castle remained unscathed during the engagement, and the XB-0 crashed a safe distance away in the mountains.[4]

Circum-Pacific War

Su-37 Kill over Stier Castle

An Su-37 Terminator over the castle

Main article: Operation Keynote

On October 22, 2010, Osean President Vincent Harling was kidnapped by Belkan operatives and imprisoned in Stier Castle. The president would remain confined in Stier Castle until December 9, at 0500hrs, when Osean fighters and marines launched a rescue operation to free Harling.[1]

An infiltration team entered the castle and freed the president, but became pinned down by intense enemy crossfire. The Osean fighters consequently punched a hole in the castle keep's west wall in order to allow the infiltration team to escape with the president. The operation was successful and, despite the aforementioned damage, Stier Castle remained standing.[1] Due to its historical and cultural significance, however, Stier Castle was likely restored following the events of December 9.



  • Stier Castle appears numerous times in-game:
  • The castle's location does not remain consistent between AC5 and ACZ: the briefing prior to "Ancient Walls" places the castle in northwestern Belka, while the briefing prior to "The Stage of Apocalypse" shows it as being southwest of Sudentor.


  1. 1.0 1.1 1.2 Ancient Walls, Ace Combat 5: The Unsung War.
  2. 2.0 2.1 Briefing prior to Ancient Walls, Ace Combat 5: The Unsung War.
  3. The Stage of Apocalypse, Ace Combat Zero: The Belkan War.
  4. The Talon of Ruin, Ace Combat Zero: The Belkan War.