Caer Suibhne is the ancestral seat of the Suibhne family, the Earls of Douglas. Situated within the mainland of Dael Riata, it is historically regarded as neutral ground suitable for high-level noble negotiations.

Caer Suibhne is in the story “The King's Peace”

• First appears - “The King's Peace,” a standalone short story detailing Dael Riatan politics
• Function: The castle serves as the primary setting for the climax of the story, where a diplomatic dinner intended to secure the “King's Peace” turns into the infamous massacre of the Murchadh leadership.

Caer Suibhne is a substantial stone castle featuring a Great Hall dominated by a large fireplace with wood panelling and flagstone floors. The castle is large enough to contain multiple corridors patrolled by guards and dedicated royal apartments for visiting monarchs. During the events of 774, it was the site where the rules of hospitality, traditionally sacred to the Suibhne family, were bloodily violated when Domnhall Murchadh and his brother Fearchar were killed in the Great Hall.

Notable people

• Alasdair Suibhne: The 7th Earl of Douglas and the host of the fatal 774 negotiation.
• Alasdair V: The King of Dael Riata, who claimed the Murchadhs attempted to assassinate him in the castle.
• Iain Alpin: The King's Steward and Commander of the Lifeguard who executed the Murchadh brothers within the hall.
• Domnhall Murchadh: The 5th Earl of Uisdean, killed here by Alpin.
• Fearchar Murchadh: Brother to Domnhall, also killed during the negotiation.
• Mister Soutar: An official or castellan for the Earl of Douglas who manages castle retainers

• Douglas: The Earldom where Caer Suibhne is located.
• Dael Riata: The Grand Duchy that encompasses the Suibhne lands.