The score was evened in July when the Douglases invested Warkworth Castle and "did gret scaith" and the victory over Northumberland at the Battle of Sark.
[3] This action in 1448 would be the last time that the two branches of the House of Douglas would act in partnership, and ride together against their hereditary foes of Percy and Neville.
In 1452 the 8th Earl of Douglas was murdered at Stirling Castle, by his monarch James II while under assurances of safe-conduct.
During this time of intermittent internecine strife in Scotland, it might have been expected that Angus would have thrown his lot in with his Douglas cousins.
So, when the rebellion began in earnest in early 1455, and the King took to the field against the Douglas brothers, Angus came out in full support of his Monarch, and was given high command within the Royal army.
The ensuing Battle of Arkinholm was a rout for the Douglas brothers, Moray was killed and Ormonde captured (to be executed soon after) and only Balvenie escaped to England.
The castle, which had been a thorn in the side of successive Scottish monarchs, contained a garrison loyal to the House of York.
On 10 August, Angus attended the coronation of James III at Kelso Abbey, where he placed the Crown upon the nine-year-old King's head, as was his right as Lord Abernethy.
In the following year, Angus spent a great deal of time consolidating his estates, placing trusted vassals in charge of the more far-flung properties.
In 1462, he received all of the goods, lands and rents of the adherents of the forfeited Douglases in Roxburghshire, apart from those already owned by his brother William Douglas of Cluny.