I found this in an interview from 2007: [quote]So from that point of view we don't have a shortage of people happy to make Halo games, but obviously there are guys that have shipped Halo games for ten years, and they are definitely ready to work on new IPs or create new things. We're actively engaged with the senior staff here on a couple of new IPs right now, but the team that can generate cool Halo games is still running full-speed as well. I'm sure those senior Bungie guys will sit in as advisors - on pre-production, design review and polishing the game as we build it - but they won't have to get their hands as dirty in the bits of pieces of the next couple of Halo games.[/quote] Sounds like some grizzled ancients did already work on new stuff while ODST and Reach were made.