You might like to focus on the beginning of the novel, and in particular how the discovery of Skellig is associated with darkness but with the hope of new life and growth. Let us remember that the narrator discovers Skellig at the end of winter, automatically associating him with the arrival of spring and new life and new growth. Also, the act of moving house is richly significant of a new start. Consider the following paragraph:
He was lying there in the darkness behind the tea chests, in the dust and dirt. It was as if he’d been there forever. He was filthy and pale and dried out and I thought he was dead. I couldn’t have been more wrong. I’d soon begin to see the truth about him, that there’d never been another creature like him in the world.
The hope and optimism that is captured through the use of darkness in this paragraph is notable. Consider the way in which the alliteration on words such as "darkness," "dust," "dried out" and "dirt" emphasises the sense in which new life is springing out of the desolation of winter. The short sentences serve to heighten this impression of darkness being symbolically used to suggest new life as a seed stirs in its soil and reaches up towards the sky. This is highlighted by the longer sentence at the end of this paragraph, that focuses on the uniqueness of Skellig and signals the miraculous events that transpire.