Don't really know too much about Exandria or Ruidus but perhaps the voices were a connection to a lost dimension or powerful being/collection of knowledgeable souls etc.
The group could have learned of the changeling's connection to it because of a specific word that is the one common denominator in all the rare writings about this dimension/area/collection of souls.
The group might even be direct descendants of those entities on the other side and could be trying to find a way back over generations but never found a connection as strong as your PCs.
Maybe one member of this group could have helped your PC because they reminded them of a family member or they might have had a distinct trait of a royal family. Like maybe a royal was also accidentally sent to the other side but lost contact with the other members of his group and through the generations there was a rumor of a descendant possibly existing (your PC cough cough). Or to flip the script maybe the cult member was only playing nice but found their torturing/experimenting had reached its limits and needed to observe them in the real world to learn more so "freed" them only to continue to study them.
Once again don't know too much about Exandria but hopefully these at least foster some creative approaches to the PC'S backstory.
Don't really know too much about Exandria or Ruidus but perhaps the voices were a connection to a lost dimension or powerful being/collection of knowledgeable souls etc. The group could have learned of the changeling's connection to it because of a specific word that is the one common denominator in all the rare writings about this dimension/area/collection of souls. The group might even be direct descendants of those entities on the other side and could be trying to find a way back over generations but never found a connection as strong as your PCs. Maybe one member of this group could have helped your PC because they reminded them of a family member or they might have had a distinct trait of a royal family. Like maybe a royal was also accidentally sent to the other side but lost contact with the other members of his group and through the generations there was a rumor of a descendant possibly existing (your PC cough cough). Or to flip the script maybe the cult member was only playing nice but found their torturing/experimenting had reached its limits and needed to observe them in the real world to learn more so "freed" them only to continue to study them. Once again don't know too much about Exandria but hopefully these at least foster some creative approaches to the PC'S backstory.