Raiden (and Raiden Drone) is a fully transformable combo model designed by Kawamori Shoji of Macross fame. While comissioned by LEGO for this (and other) promotional designs, they are not part of Exo-Force due to copyright ownership by SATELIGHT (copyright holders of Macross).
This combo model's instructions and sticker set were awarded for purchasing a special three-pack of LEGO Exo-Force sets at a number of conventions in Asia.
Raiden is fully transformable from a vehicle mode to a GERWALK (half-and-half) mode, and finally to a humanoid mecha with minimal to no removal of parts other than the Raiden Drone.
Highly detailed and complex, it is intended as a display model rather than a playable toy due to being a bit structurally weak from the stud connections. This doesn't seem to be a problem if the parts are secured with a weak water soluble glue for stability.