This is something that I have been wondering for a while, what if when Margaret Maid of Norway dies in 1290, or if she dies even earlier say in 1286, Robert De Brus, Fifth Lord of Annandale decides to act and seizes the throne and is crowned King at Scone through all the proper channels?
Obviously Balliol and Comyn would rebel and fight, but who would join them? And what of Edward I what would he do?
Thinking about it, the Bruces would have a fair bit of support as one of the most powerful families in Scotland, it seems as though the country might well be torn in two, so perhaps Longhshanks comes north to try and 'settle the dispute' and to put a puppet on the throne.
House of Bruce:
King Robert I Bruce, Lord of Annandale (1210-1296) reign as King 1290-1296
King Robert II Bruce, Lord of Annandale (1243-1306) reign as King 1296-1306
King Robert III Bruce, Lord of Annandale (1274-1329) reign as King 1306-1329
these are the first three Bruce Kings of Scotland, with each one holding the title Lord of Annandale, they would of course be contested by the Balliols and the Comyns and the Bruces other enemies.