Mostly I am just wondering if the situation has ever arisen where the head of the Commonwealth was ever the head of state of two countries that were warring with each other. I would be happy with war between countries in the commonwealth before it became the commonwealth of nations, with republics and whatnot.
I realise that I utterly butchered the title, sorry.
One case is the Indo-Pakistani War of 1947-48, also known as the First Kashmir War, in which both countries vied for control of the princely state of Jammu and Kashmir. (The princely states had been indigenous monarchies under British suzerainty, and in 1947 each one was, in theory, presented with the choice of acceding to either India or Pakistan, or remaining independent.) A notable result of this conflict was the Line of Control which is still used as a de facto boundary between India and Pakistan. Pakistan was a dominion until 1956, and India until 1950, so George VI was head of state of both countries when the conflict took place.