Raven Does not have a story on episode mode but you can watch Soul Badguy story and see what Raven is doing before the main story.
Here is the link for Sol Badguy story:
http://www.dailymotion.com/video/x4fq1w1_guilty-gear-xrd-revelator-sol-badguy-story-arcade-no-commentary-ps4_videogames
