Developing a Necromancer hero.

Actually, the wheel states that the gold and resources gained through this skill depend on the number and quality of defeated units. From this, we can conclude that it is not beneficial for a secondary hero to develop this skill, as it would require them to sacrifice a significant portion of their army to attack reasonably strong mobs. However, in that case, the secondary hero would gain experience instead of the main hero. Furthermore, I believe that taking "trophies," as well as "luck of the road," is only advantageous at the beginning when you are building up, but after that, these skills are not particularly useful. So, for example, on small maps with well-guarded mines, I think it might be worth taking, at least "luck of the road" for sure.