This was an okay fantasy. I found it a bit predictable, and it felt like a lot of things were skipped over, but it was still an interesting magic system and a fun idea.
The story follows our titular Assassin Thief, Telium, who has been hiding away for 50-odd years in the forest after the death of the Queen she served. When fae warrior Mallux comes seeking aid, she accompanies him on a quest to save the world.
Firstly, 'thief' seems to just apply to magical humans, not people who steal things. That was a little confusing at first but easy enough to figure out when they start naming other kinds of thieves.
Second, I didn't really like either of our main protagonists. Telium seems a little slow on the uptake, frustratingly not even considering why she's lived 50-odd years without visibly aging. Mallux seems domineering from the get-go, and constantly calls her pet?! and she's okay with it??! He really bothered me, I did not like him at all.
As the story progressed, it all seemed rather obvious to me where things were headed, which made me more frustrated at Telium not questioning things. I found there was a lot of attention paid to the relationship between the two, meaning the world-building suffered as a consequence. This is my number one gripe with this insane wave of 'romantasy' books - the story and setting is more often than not sacrificed in lieu of flirtatious glances and marveling over muscles under tight-fitting clothing.
That said, the writing is fine and I think people who have read less fantasy may be more surprised at things that happen.
I still mostly enjoyed the journey, but it would have been more satisfying if it went in a fresh direction. As it was, I found the predictability made it a little tedious for me, but I think other readers might handle it a little better. The romance was also painful to me but I think I've been pretty upfront about my dislike of mooning and explicit scenes in fantasy books.
An enjoyable enough read for the most part, though not enough for me to continue with the series. This is one for fantasy fans looking for familiar tropes and charged, slow-burn romance.