Does this mean he finds all five artfacts at once?

Question

Five artifacts in his quest he finds.

Answer 1

You cannot make any kind of inference as to whether they were all found at the same time. The quest could have taken five years to complete, and he found one per year...or all on the last day.

Answer 2

The timing is not necessarily specified in the context of the writing. The text is inferring that the artifacts, five of them, were found during the quest but not necessarily at the same time. All the best.