This was requested by several people, so here you go! enjoy!
Originally I was going to place a Binary Rifle in Chief's left hand (since it was long enough to fit in a similar fashion to how Doom-guy was holding it), then I removed it due to fitment issues, then I had a lightbulb moment and added Cortana
I think it worked out quite well
DOOM © ID Software
Halo 4 © Bungie, Microsoft Studios