So I was going about building a beast faction. When I got to the classes I thought "Oh all I need to do is move from one class to the next" like how humanoids create classes
I did not realize that this is not how beast factions create units. They go from the base faction, not from other units.
Biests are not as skill oriented as Humanoids. More focused on raw stat increases.
Humanoids are the only domain that builds primarily off other classes.