The master_chief.zip file you have requested: Garry's Mod / NPC's / Garry's Mod: Master Chief NPC Halo - 15.85mb is not available. Perhaps try browsing all files for the game Half-Life 2 and upload any files you want to share or are missing. This is the only information we could locate:
This is a civilian-based NPC, from halo. Master Chief! Enjoy.