The alien creatures did not kill the disciples and elders of the Eternal Divine Court because they felt they needed the martial artists as cannon fodder, or they could learn a lot of professional knowledge from those martial artists.
Some alien creatures can acquire all the past memories of a martial artist and gain various knowledge from those memories.
For example, how to refine elixir pills and how to forge dark weapons.
For alien creatures, they are not good at refining elixir pills, nor are they good at forging dark weapons.
After learning that knowledge, they can make themselves capable of refining elixir pills and also of forging dark weapons.
If those alien creatures do not want to do it themselves, they can have the captured divine world martial artists refine elixir pills and forge dark weapons for them.
Therefore, those alien creatures left the elders and disciples of the Eternal Divine Court behind.
