Uriel does an amazing job at establishing stakes fairly early on with how the story handles Isayah's mother, notably when it comes to illness as well as work in the mines. As the stories go on, more stakes are introduced, such as other ailments or the punishments the slaves receive, further reestablishing the consequences should Isayah fail. More important than all of this, the stakes are more than just empty threats as the protagonist is forced to come face to face with the consequences of his actions and the brutality of the world he was reincarnated into.

Now onto motivations. The important named characters all feel as though they have proper motives and reasons for the things they do and why they do them and these motives are both clear, and understandable. The reader is also regularly subjected to events in the story which show and explore these reasons, creating a deeper understanding of these characters in the process.

If I had anything critical to say it would first be that the isekai aspect of the story feels underdeveloped. While there are elements telling you the protagonist is from another world, Isayah frequently comes across as more of a prodigy or chosen one than someone from another world to the extent where, if it weren't for being told he was an other-worlder, all of his actions felt as though they could be explained by one of the two, or by him simply being a "weird" kid who knows things. For better and worse, he very much so comes across as a product of and part of the world he now inhabits.

The other criticism I have of Half-Elf Messiah is how the struggles involving his family near the end felt, while still done well, felt somewhat rushed, abrupt, and a bit forced at times, especially with what happens with his mom at the end.

Overall though, I'd say Half-Elf Messiah is an amazing read, well worth your time. It quickly sank its teeth into me with its ambience, tone, and likeable characters.