Donald III (Domnall Bán Donalbane), brother of the murdered Malcolm III, was twice King of Scotland between 1093 and 1097.
In 1094 Donald was deposed by his nephew Duncan II who only lasted around six months before being killed when Donald, aided by Edmund, second son of Malcolm III and his widow Margaret (St Margaret).
It seems that Edmund was then given a share of the kingdom perhaps in anticipation that if Donald had no son Edmund would succeed in his own right.

However both were deposed when in 1097 Edgar the fourth son of Malcolm and Margaret, with the support of William II of England, came north with an army.
There are differing stories about Donald’s death. William of Malmesbury said he was killed by David (later David I) However the Scottish king-list, documents that he was captured and blinded by King Edgar in Rescobie, Angus.
A.A. Duncan notes in the Oxford Dictionary of National Biography an entry in the Annals of Tigernach which said he was blinded in 1099, probably the date of his death. Also that he was first buried in Dunkeld but that “Iona holds his bones.”
Although the name of Donald’s wife is unknown he had a daughter Bethóc, from whom John Comyn of Badenoch (d. 1302) derived his claim to the throne in 1291.
Donald III was succeeded by King Edgar.
The British Royal Family – more information
If your interest in British royalty goes beyond Scotland’s earliest kings and queens, see the official British Monarchy website for lots of additional information.