World Specialities
Every world had unique specialities that were cultivated in it in secluded locations. If suppose Fenn were to grow and develop further, he would establish a powerful Clan with the Invoked Spirit of Garuda.
This power whereby they can grow by absorbing Mental Fragments from both humans and eagles would be their exclusive speciality, not to mention being able to create invokers without an Invoker Crystal but using the egg that the Garuda produced.
Such specialities would be targeted by System Hosts who would exclusively gain that power. And once they leave the world and are consumed by their Hosts in the System World, their System would gain that power permanently.
If the absorbed essence was strong enough, the System World would condense it into a Skill to bestow the System with.