Top pic not related... just reminding you that OOO has more medals to get!
According to dukemon22, one of the most credible sources in terms of Kamen Rider rumors, he reveals to us the possible origins and details of the 2nd Rider.
- 2nd rider is created by Kougami "improving upon" the OOO Driver
- Both the feet and hands of the rider have "holes" where it seems Cell Medals can be inserted.
- The rider's hand actual transforms into his own "ArmsScanner" which acts like OOO.
Aside from that, according to KamenRiderBiblio, there is a single-person company who is offered to create the designs of the 2nd Rider! Accordingly, the design resembles OOO, with the medals and all. His head has the shape of a large bird, with the scanner being crowded because it is placed in the arm.
Take note, till there is confirmation coming from Toei, take this as a grain of salt.