There are a couple of things we need to cover when we talk about style in The God of Small Things. One important aspect of the novel's style is the way it takes into account each character's personal history. This is not to say that each character is a protagonist, or that we know each character equally. Like the epigraph tells us, there is more than one way of telling a story. (See "What's Up with the Epigraph?" for more.)
Even though we largely see the novel from Rahel's perspective, we get a pretty good idea of each character's back-story. This is important because we learn certain things about the characters that are only known to them. Our experience of the story would be totally different if we were only following one person's point of view – we'd be missing out on a lot of key information. One interesting way in which Roy creates a distinct point of view for Rahel and Estha is by capitalizing certain words or phrases. We see how kids envision particular ideas as being very important.
The other crucial aspect of the novel's style is that the narrative is nonlinear, meaning that we experience the events out of order. We know at the beginning that Rahel and Estha are being reunited as 31-year-olds after being separated over 23 years ago. We know they are the same age now that their mother Ammu was when she died. We know that Sophie Mol is the name of a girl who died when they were kids.
Then, when we read further, we go back in time and meet these people as living, breathing characters. We know their fate ahead of time, but we have to jump around in time to figure out how the events happened. The novel doesn't just jump back in time once and then move sequentially into the present. Instead, we find ourselves alternately in 1969 and 1993, collecting the pieces of the puzzle until we know in the very last lines of the very last page exactly how we got to the moment we saw play out on the first page.
The narrator reinforces the concept of knowing what happens before we see it happen when Rahel goes to see the kathakali performance in 1993:
It didn't matter that the story had begun, because kathakali discovered long ago that the secret of the Great Stories is that they have no secrets. The Great Stories are the ones you have heard and want to hear again. The ones you can enter anywhere and inhabit comfortably. They don't deceive you with thrills and trick endings. They don't surprise you with the unforeseen. They are as familiar as the house you live in. Or the smell of your lover's skin. You know how they end, yet you listen as though you don't. (12.8)
We're not saying that by making this observation, the narrator is saying that the story he or she is telling is a particularly great one; that's up to us to decide. The key point of this moment, though, is that it draws our attention to the way the story is told in the first place. Like Rahel at the kathakali performance, we jump into the novel at random points in the characters' lives and figure out the story from there.