The words fierce and shades have multiple meanings; what do they mean in this context, and can you suggest another meaning?
"The actual soldier of 1862-'65, North and South, with all his ways, his incredible dauntlessness, habits, practices, tastes, language, his fierce friendship, his appetite, rankness, his superb strength and animality, lawless gait, and a hundred unnamed lights and shades of camp, I say, will never be written -"
In the phrase "fierce friendship," the word "fierce" seems to mean that the friendship was extremely strong, that friends would defend each other to the death.
Some synonyms of fierce are: ferocious, violent, cutthroat. However, none of these meanings seem to fit here.
In the phrase "a hundred unnamed lights and shades," the word "shades" seems to refer to particular details and nuances. The word shade, of course, can refer to a shade of color: a light blue, a deep orange, etc. Here, it is used metaphorically to describe various "shades" of people and personalities.