It is confirmed that Shura is going to be Kamen Rider Black Baron Banana Arms. The reason why he had transformed into similar body as Kaito's Baron might be because they both were aiming to get greater power.
All this we have been thinking that who will Zack fight in Gaim Gaiden? The Answer is this Armored Rider!!
Well, he is not the original Baron & not even Neo Baron.
He is Kamen Rider Black Baron!! Probably this might be the Armored Rider form of Neo Baron's Leader → Shura. He uses Banana Lock Seed.
A New Evil Armored Rider is going to appear in Gaim Gaiden: Kamen Rider Duke. He is called Kamen Rider Saver. It is not known just who is going to transform into this but there are rumors that Ryoma's Predecessor Kugai Kudou will be going to.