Claudio is a new Character to the Tekken uninverse. Just recently Namco gave a synopsis of reason in being in the game. Check it out:
“TEKKEN 7’s engaging story mode is composed of several hours of gameplay (including side stories that players can unlock progressively). Not only can you play as the Mishimas in Story Mode, but there are other arcs that involve fighters outside of the Mishima clan, such as Claudio Serafino, and his group of exorcists.
The Archers of Sirius are a group of exorcists who have been banishing supernatural entities from this world since ancient times. A highly secretive organization, its existence is unknown to the public. Although it is not known how their existence was revealed, the Archers of Sirius were suddenly approached by the Mishima Zaibatsu. They were heavy-handedly requested by the Mishima Zaibatsu to join their conglomerate, but naturally refused. This did not stop the persistent pressure from Mishima Zaibatsu, however.
Eventually, the news of this approach from the Mishima Zaibatsu reached the de facto leader of the Archers of Sirius, Claudio Serafino. Determined to uncover the motives behind the Mishima Zaibatsu’s actions, Claudio begins to investigate the powerful conglomerate.”
Here is some new screen shots as well.