As X-COM grew, the Commander decided he needed an additional level of "deputy commanders" to manage day-to-day issues in the different branches. Bradford was, of course, the obvious choice for Deputy Commander for Operations. But since Shen and Valen were both too critical in their hands-on roles, the R&D branch needed a dedicated manager to coordinate their activities from a higher level.
After a brief search, the Commander chose a new Deputy Commander for R&D: Cave Johnson.
After a brief search, the Commander chose a new Deputy Commander for R&D: Cave Johnson.