Phew, chapter 6. This book is very dense and it's only just starting to pick up in pace too. Once again, I will not post a synopsis (to save time), but will instead point out bits and pieces I find interesting.
First, the knight says "....lest the same evil... overtake the the singer that has befallen the knight." So I find this interesting because he defines himself as "the knight" and the narrator as "the singer". So here they are clearly typed. I believe these are both metaphorical types, though to be honest I don't have a clear picture of what they stand for. This is something I am still pondering, as these tropes will show up later in the story as well.
Another point I find interesting is how the narrator thinks "remembering how my songs seemed to have called her from the marble, piercing through the pearly shroud of alabaster...why... should not my voice reach her now, through the ebon night that inwraps her"? So it's like these are described as different types of shrouds, one a shroud of alabaster and the other a shroud of ebony. It's possible this was just meant as a literary device, but it seems to also portend some sort of allegory. Again though, I don't know exactly what.
The rest of the chapter is consumed with the Maid of the Alder Tree. Once more, this figure is an obvious allegory and is a sort of parallel to the Ash. While the Ash represents a sort of male vampirism (see my prior post on Chapter 4 for more discussion of Ash), the Alder tree is described as a sort of female vampire (in later chapters she is discussed more, I am melding that discussion into here). Just like the Ash, the Alder is cursed with a hollowness, an emptiness inside that she tries to fill by manipulating others and consuming their love, like the Alder tree tries to consume people's bodies.
They also use different means of entrapment. The Ash tries to manipulate your fear, the Alder tries to manipulate your desire, to steal your desire and devour it. They are different manifestations of the same spirit.