It is unusually high quality Harry Potter fan fiction, and teaches you as you read it. It was engaging enough to upset me when I got to the end and realized it was incomplete.
Draco and Lucius' re-explored relationship is one of my favorite parts of this story. Completely ruthless people can love just as tenderly as conventionally moral ones. I originally intended to have the Patronus curled affectionately about the cane, but then I decided this expression of Draco's soul would have more of a sense of decorum, and that loving, awe-touched admiration is a more apt expression of his feelings for his father than straight up cuddles.
The pictures I found of the Blue Krait tended to have it being mostly blue with pale stripes, but I think reversing the coloration makes it more appropriately silver and glowy. And it's no loss to the snake since I expect the Patronus is largely unconcerned with being able to hide in tall grass.