Savage is rarely a good thing to be in The Faerie Queene. The other Savage Man we meet, who also is known as Lust, for example, is a rapist cannibal—yikes. But this Savage Man, who we meet in Book 6, is a representation of the potential of human beings to overcome their circumstances.
While he has no education or even language, he learns compassion and loyalty from observing Calidore and Calepine. Not so unlike the incident with Tristram, the Savage is another example of how knightly qualities can lurk in people who aren't strictly knights. The Savage man is also a kind of foil to Calidore's courtesy, which an example of the refinement and elegance of courtly life.
The Savage Man, in contrast, is someone for whom both refinement and elegance are totally unknown, but he still shows a basic instinct toward good and kindness, reminding us that courtesy is important, but not the only means of being a good person. The Savage Man's simplicity foreshadows the simplicity of the shepherds later in the book.
Like all Spenser's depictions of savages in the poem, however, there is a disturbing racial element that colors even the representation of a good character like the Savage Man. Relying on stereotypes of native and aboriginal people that were becoming prevalent with the conquest of the New World, Spenser here crafts a figure of the "Noble Savage."
The "Noble Savage" was a figure painted as ignorant and uncivilized, but nonetheless deeply good. Indeed, his lack of civility was sometimes connected to his ability to be simpler and more genuinely honest. While certainly a nicer stereotype than the one we see informing the representation of Lust, it remains problematic and reductive of actual native peoples and cultures.