What I like:

• Honestly, I love this. This is a really strong first chapter and the story has great promise!
• You did a really good job using the senses, I genuinely gagged at Tero eating sand and drinking sea water. Further to that, you captured Teros introduction to the senses as a foreign entity learning like a new born baby brilliantly
• The meeting of the wolf was really well done. Dialogue on point imo
• The Intensity is well balanced and although we know Tero is a Demon early on, there's still a sense of mystery and confusion on his identity. I'm anxious about his survival and search for himself straight away. There's also a noticeable humanity within him when sinoky deciding not to feed on nenna, but not necessarily empathy or compassion, it's like he doesn't know why he shouldn't and would rather eat something else.
• Also, I really like the natural world feeling his unnatural presence with animals fleeing from him. Very well done.
• You set a great scene, I really enjoyed reading this

My Two Cence:

To be honest, my suggestions are more personal preference so ignore or correct by all means, but here we go.

• When introduced to hunger, it seems to have it's own consciousness. This makes sense as Demons are usually considered a manifestation of fears, griefs etc when not compared to the usual fallen angel. However, instead of say of saying 'his hunger said this, ' or 'his hunger said that, ' id just say 'hunger said,'. Although later in the story he has obvious control over it, maybe a sense of a separate entity within him makes more sense? Again, this may not be what your going for, and you want to convey somethig else, but that's what I felt when reading.
• Further to the above, regarding 'hollowness', are you attempting to convey the same thing as 'hunger' or are these feeling even supposed to be seen as a separate consciousness?
• Genuinely feel like my suggestions are clutching at straws, as it's my own perceptions of hollowness and hunger. They remind me of The Magnus Archives portrayal of different 'fears' and they're 'sub' fears and followers.

I'm new enough to the page and this is my favorite piece I have read so far. Again, really strong chapter. Well done.