According to story artist Louis Gonzales, for the DunBroch castle, the production team didn't want a Germanic Cinderella-like castle, but an “earthy” castle, grittier than the pristine ones often seen in animated films. For inspiration, They visited the Eilean Donan and Dunnottar Castles.
The DunBroch, MacGuffin, Macintosh, and Dingwall clans were once enemeys locked constant war, but when Vikings, Romans, and Northern invaders threatend them form from the seas the 4 clans joined togather under the sword of Fergas to defand there lands. Evuntuly they succeded in protecting their lands from the invaders and formed Kingdum DunBroch and crownd Fergus their King and Elinor their Queen.
Each clan has a Relic/Symbole.
The DunBroch Clans symbol is the Sword: The migthy sword represents Bravery and the proction of the kingdom.
The MacGuffin Clans symbole is the Cauldron: With one moldy potato the magical Cauldron feed the entire clan, giving them the strangh to slay 10,000 Macintosh in battle.
The Macintosh Clans symbole is the Lyre: The Lyre slayed 1,000 Dingwalls by playing a magical tune.
The Dingwall Clans symbole is the Rock: An anchint relice held by the clan.