Malcolm I (ruled 943-954). Malcolm I succeeded his second cousin Constantine II, who abdicated to enter a monastery. In 954 Malcolm captured Moray, a kingdom to the north, and killed its king. He also made a pact to assist England against the Scandinavians, but he later turned against his allies and captured territory in northern England. Malcolm was killed while trying to put down a rebellion in Moray
.Constantine II named his second cousin Malcolm as successor. In those days, in order to stamp your authority as a King, you were expected to wage war and claim your prizes as any strong, worthwhile King would - and Malcolm was good at this part of the job.
Cleverly allied with the English now, Malcolm and his new found friends marched on to stamp out the Scandinavian threat from Ireland. But in 950, with a little pushing from Monk Constantine, Malcolm moved into England and started taking the northern territories there.
However, on his return from his crusade in 954, Malcolm had now found that his own northerly regions had revolted and in a brief conflict with them they killed him at Fordoun in the Mearns.
http://www.highlanderweb.co.uk/monarch2.htm
King of Scots 943. Killed by the men of Moray 954.