[She would think that if Locke had an enemy here, he would have warned Terra when they saw each other. Which leaves the known enemy and Hades who is very likely an enemy. And stealing a single person with no outward sign just doesn't seem like something a god would do (but really, she knows nothing about Hades beyond traditional Greek myths).]
Then we may have to assume, at least for now, that the darkness took him back.
[Avast! Here there be Action!]
Then we may have to assume, at least for now, that the darkness took him back.