The Grangerford clan is Twain's example of a traditional aristocratic family living in the pre-Civil War South. They’re extremely wealthy: each family member has his or her own personal servant; their house is huge and beautiful; and they own a ton of land with over a hundred slaves (we’re thinking they live on a plantation). When Huck stumbles into their lives, the Grangerfords treat him with the utmost hospitality and care, but only after they discern he has nothing to do with "the Shepherdsons."
Oh yeah, there’s that little detail. The Grangerford family, as pleasant and respectable as they can be, live in a world of fear and hate. They’ve had a hardcore feud going on with the nearby Shepherdson clan for about thirty years, and each family is intent on killing off the other, one by one, until no one’s left standing. Even Buck Grangerford, a boy around Huck’s age, has violence on his mind all the time.
When the fighting breaks out while Huck is staying with them, he witnesses one of the most tragic sequences in the novel, made all the more upsetting by how endearing Huck finds each family member. We think Twain might be trying to show how so many great people met a needlessly tragic end by following traditional codes of honor. (You may want to check out what we have to say about The Shepherdsons in order to get the full picture.)