I had totally forgotten about The Brecilian Forest codex entry, but as I read it I looked for the bows available in Trespasser... and they also happen to be three, just like the ones Abelas (from the codex entry) crafted from the tree.
Arrowwood, with a description that features a Witch of the Arbor Wilds and her daughters...
The Bow of Artifice, crafted with odd mods and that sound like "irritating birds". ("When you fire your bow, it hums after, every time.")
And Elgar'nan Enaste ("The approval of our spirits"?) which features the inscription "Your people call out for all things to end in flame. Ashes sing Your Praise."
Elgar = Spirit + 'nan = Our Spirits
Enaste = Favor, approval
Out of these three bows, Arrowwood is obtained almost mandatorily while progressing on the Trespasser DLC storyline, while the other two can only be obtained by completing two of the optional trials.
My point is: we're supposed to see Arrowwood and read its description, because it seems like it matters more.
"An old Ciriane tale speaks of an archer named Arrowwood who traded his heart to the spirit of an oak grove to become the greatest archer in the world."
Curiously, the tree mentioned in The Brecilian Forest codex entry speaks of a tree that holds a hunter's spirit within...
Sera could be a tricky card under the writers' sleeves, since it's rather easy for her to seem randomly nonsensical and even impulsively violent (especially during her personal mission, if certain dialogue options are selected,) which can make her seem... a bit hostile at times.
It's like it's difficult to even like her at first (at least, that was my case considering she lied her way into the Inquisition and then she was also needlessly aggressive).
But what if she turned out to be something more?
I'm not sure about her having a spirit within, or even having some connection with Andruil at all (which has been a strong theory for a while now,) but there's definitely something about Sera...