[806mtson]

Just passing through again, but I don't think that they would have a "Family-splitting arc" unless it debuts a new form for Revi that is a Berserk Form, which, ehh, I don't think so.

But, I think that I will be doing something. Here is a list of all Vistamps currently known for the Legend Riders Vistamps:
Kuuga: Lion
Agito: Unknown
Ryuki: Unknown
Faiz: Ptera
Blade: Unknown
Hibiki: Unknown
Kabuto: Unknown
Den-O: Mammoth
Kiva: Unknown
Decade: Megalodon
Double: Eagle
OOO: Unknown
Fourze: Kong
Wizard: Unknown
Gaim: Kamakiri
Drive: Unknown
Ghost: Unknown
Ex-Aid: Jackal
Build: Supposedly Kangaroo
Zi-O: Brachio
Zero-One: Neo Batta
Saber: Kajiki
1: Batta
V3: Turtle
X: Scorpion
Amazon: Mogura
ZX: Kujaku

So, we still don't know for sure the identities of the Stronger, Skyrider, Super-1, Black, Black RX, J, ZO, Shin, Agito, Ryuki, Blade, Hibiki, Kabuto, Kiva, OOO, Wizard, Drive, and Ghost Vistamps.

Though, I am a bit hesitant of saying that the Build Vistamp is the Kangaroo Vistamp considering we have the Kangaroo Proto Vistamp and it clearly isn't Red and Blue. This is why I am a bit hesitant of calling that the Build Vistamp would be based upon the Kangaroo.
Oh, I forgot to mention the Condor Joker Vistamp. But Joker isn't a Main Rider so it technically doesn't count.