I haven't played that game so I wouldn't know
But it sounds very similar. These traits wouldn't be seeded based on enemy type (though different enemy types could have different pools of traits). The idea being that enemies have a base/core class and stats, and that 0-3 traits (which can be negative or positive) are seeded on each enemy.
This way you could fight a bunch of enemies in a room in one game, and on a replay, the same encounter could be vastly different because both their weaknesses and strengths and their AI behaviour would play out differently.