Outstanding work from two relatively new authors! Brave attempt at developing a new class. The best thing about it is the in-depth story rationale for its construction as a unique class, instead of as a subclass. This is usually pretty rare.
There are definitely aspects that can be tweaked for balance. For example, I wouldn't grant a new class proficiency in two common saving throws (CON and WIS). I'd pick one of them and pair it with an ability like either STR, INT, or CHA. In addition, the wording of particular phrases could be made more consistent with the wordings from the PHB, at least when explaining a rule. Patches of this I'm sure will be corrected in future iterations.
I encourage everyone to give this a purchase and provide some constructive feedback to the authors, who have clearly taken their work here seriously.
[5 of 5 Stars!]