Random Artifacts can be drop by picking the right dialogue choice in the story.

-San take the jewelry from the boy.
After killing the Ice wolf dragon the artifact will drop.

- Escort female samurai back home. (you will pass this level again)
Misharashi comes to you after starting the level over first room.

-No dialogue choice for lily after taking out the monsters a cutsence with wendy a Artifact will drop.

-We send the Kunoichi to the camp = Forgive the kunoichi.
Alas comes to you after starting the Volcano level.