Zigfried Von Schroeder's Polymerization.

I was just taking a casual browse through the YGO wiki and as I was taking a peek at the list of people who used a polymerization in their deck I noticed that Zigfried (the Valkyrie user guy from DM) is registered among them. However, as I took a look at his anime deck, I realized that he doesn't even have a listed Fusion monster whatsoever and it really makes me wonder why he even has a Polymerization in the first place when he can't even use it to summon anything. Does this mean Valkyries have a secret Fusion monster that we don't know of?