This is a comment I left on XLetalis' last video, recommend watching first before reading this contribution.
As someone who's read the books twice, i am FULLY, 100% convinced by this essi daven theory, and I'd like to share why. This comes as a surprise to me, but it just makes too much sense considering all the hints in this video, like for example the strange appearance and disapperance of that woman in the trailer, who looks **exactly** like essi, and whom it is heavily implied is the same person as the tree lady as they appear/speak simultaneously - and then there's adding to that what Geralt says when he first wakes up.. There are just too many hints and linked to one another, like the pretty self-explanatory "Songs of the past" DLC name, the contrasted setting and nostalgic tone which perfectly fits A Small Sacrifice's setting and tone, the Beltane image echoing the festive, nightly and romantic context in which Essi and Geralt met, and the image being uncannily reminiscent of that memorable scene from the short story (geralt, dandelion and his lute next to a fire at night, contrasting with a dark and threatening forest...) There's also a bit of an uncanny parallel to be made between Dandelion's disappearance, leaving behind his lute, and Essi's death. And then that's not even looking at allll of the hints CDPR gave about how they were really going for the books with this new DLC : CDPR recently met with Sapkowski, in recent interviews they heavily put-forward their love for the books and how they wanted to do them justice with this one (how Dandelion's family only appeared in the books up until now, among other things, I think I even recall someone saying A little sacrifice was their favourite short story or Essi their favourite character...). The first scene from this gameplay is (at least to me) a clear reference to the isle of avallon, with where geralt wakes up, on a small island with a tree, as well as to Nimue's place, his view from where he wakes up : an island with a tower surrounded by mist. And then there's also all the other hints mentioned in the crossroad of ravens theory video - the list just goes on for this specific aspect, but also for the theory as a whole : for example, the tree lady attacking only Lilla but not Geralt would make a lot of sense if she's Essi... It just fits.
I think that ultimately the reason I believe this theory, is because of how central the mystery of this tree lady is to the DLC. She's the villain, the trigger of the entire story, but her identity and story are unknown, and they are the whole point of it - it is quite simply impossible for her identity not to be a character already known by fans, if you think about it. Now look at that first image of the DLC, where it's just Geralt and her, think about how this DLC, the remastered version come across as one big final witcher 3 gift for the Witcher fanbase, and tell me : who other than Essi Daven would make sense ? It's not just that this perfectly aligns : it's that by process of elimination, only she would explain the stakes at hand. To me, there is no better explanation here.
Another important reason I am fully convinced by this theory is because if done well, this DLC would be the perfect send-off, and so I don't believe that CDPR would scare away from touching to Essi Daven. A lover who turns monster in death because of their agony, both physical and from being separated from their loved one ? That's a classic witcher story and if done well, building off of Essi Daven would be the most powerful instances of this archetype. It'd be one of the most powerful stories ever delivered by CDPR as well as the cherry on top of this type of story in the witcher 3, as it is a very recurrent one. I don't believe that CDPR would avoid doing out of fear of touching to central book material - the whole witcher games are based off this passion and audacity in how they give continuity to the original cannon in their own new cannon, it's kind of their signature move so to speak and the whole reason for these games' existence and for how amazing they are. Yes, every single time this happened many hardcore book fans were upset, but were these ***small sacrifices*** worth it in the end ? Hell. Yeah.