The original Halo developer credited in notes for Halo: Campaign Evolved is Bungie. Bungie created Halo: Combat Evolved and established the series’ characters, combat systems, art direction, and science-fiction setting before the franchise moved to other development teams.
Bungie’s original work is central to Campaign Evolved because the remake retells the campaign that first appeared in 2001. Halo Studios has described the new game as a ground-up remake, but its developers also studied original production materials, including development assets and storyboards associated with Bungie’s version of the game.
Bungie is sometimes confused with Ensemble Studios, which developed Halo Wars, or Rare, another major studio within Microsoft’s broader gaming history. Epic Games is the creator of Unreal Engine, the technology used by Campaign Evolved, but it is not the original Halo developer. Bungie later created Destiny after separating from Microsoft.