At first many of those fighter families decided to use some of their family members as the reproduction option for the family. Naturally they would get help from those elfs and at the same time everyone of those people who will become the reproduction option for their family naturally will lose their freedom and they need to continuously store spiritual energy in their blood.
You can say that was a very painful process and many of them already died because of this. But still many of those fighter families used that previously to create powerful fighters for their family and as you can tell Alex right now got to know about this and naturally he became mad about this.
