This is it, folks, the moment we've all been waiting for. Gil has done the training montage. He has seen the elephant by beating an honest-to-fey elf with a stick. He has earned the right to wear his father's armor and carry his father's sword. Though he has no liege to serve, and does not yet wear the spurs of full knighthood, he stands strong and proud.
Gil is aided in his fight by, of all things, a cardinal. Again we see Wright's strength as a writer, as the Cardinal has a voice unlike any other. Even unlike those of birds encountered earlier.
He is also aided by the tree itself, who gives up its life to save that of Gil and the child that he seeks to rescue from the snowtrolls. As the cardinal says, "Christmas trees are not like other trees." That's a great touch that shows Gil is not alone in his fight against creatures from the elfin side of the universe. Even the trees, part of God's creation, will stand to fight against evil if given half a chance.
In addition to Gil's first real test as a knight, this marks his first chance for vengeance against members of the Cobweb family, and against the creature who kidnapped his mother and killed his father. In this chapter we meet the Winter King, and though he recognizes the Swan Knight's armor and sword, he cannot determine who wears the blue and white. Though powerful, he is not all-knowing.
And now we see Gil come into a bit of wisdom. Naming himself the Son of the Swan Knight would spare him combat against the three invulnerable trolls, but would earn him the ire of far more dangerous foes. Instead of taking the expedient route, he maintains his anonymity. It's a small thing, but not a minor thing. Gil's physical growth, and his increasing knowledge, are matched by increasing wisdom. He shows this trait once more when he spares the life of the troll that tortured his mother so long ago in exchange for the life of the kidnapped baby that sucked him into this fight.
It's a gesture both wise and compassionate, and he is rewarded for his efforts with several superpowers related to the beasts slain. Tasting the blood of the slain earns him the gifts of hearing true, seeing true, and speaking true - of the last, it affects others more than him. They will hear the truth in his words. All very appropriate rewards and powers of a chivalric knight.
Of course, he is not perfect, as we see in the final chapter...