From your comments, you are asking if "country of will" and "will of country" are interchangeable. They are not.
Your example: "War is a country of will, there’s no room for sympathy.", is a metaphor which likens "War" to a "country (of will)". It means that "War" is a big thing with lots of different features but all of them represent "will". For "will", we assume the noun definition (summarised for simplicity from TFD, American Heritage):
3 A desire, purpose, or determination, especially of one in authority
The metaphor is of a large country where "sympathy" does not feature. They phrase "no room" links to the idea of "will" as a spatial area (a country).
On the other hand, "will of country" is not necessarily a metaphor. A country can have a will and can express it in democratic processes. The speaker is not saying that war is necessarily the will of a country. They mean that when people are engaged in war, they do not show sympathy.
Another example of this kind of construction is "people of integrity" or "integrity of people". "People of integrity" are people who show a lot of integrity. These people were trustworthy because they were people of integrity. "Integrity of people" does not necessarily mean there is a lot of integrity. I'm never surprised by the integrity of people. The two phrases are not interchangeable.