Forge/Halo 5: Guardians
From Halopedia, the Halo wiki
Not to be confused with Halo 5: Forge, a free standalone PC application.
Forge is a gamemode featured in Halo 5: Guardians. Unlike previous Forge modes, Halo 5 did not ship with Forge on launch, with the mode instead being released as free downloadable content as part of the Cartographer's Gift update on December 16, 2015. Unlike the Forge modes of the previous two entries - Halo 4 and Halo 2: Anniversary - which were both based on the Forge 2.0 introduced in Halo: Reach, the Forge present in Halo 5: Guardians has been rebuilt from the ground-up to more resemble a map creation kit than a simple editor. While Forge can be accessed through the Halo 5: Guardians game for Xbox One, the mode is also playable on Windows 10 PCs due to the release of Halo 5: Forge, a free standalone application for PC players to use to create and edit maps.
Changes from Forge mode featured in Halo 2: Anniversary
Halo 5: Guardians features the most comprehensive overhaul of Forge functionality since the implementation of Forge 2.0, three games prior.
All forge objects can now be placed on all maps regardless of map size, allowing users to Forge on any map. However, Halo 5: Guardians shipped with several designated Forge canvas maps. In addition, new Forge features allow players to customise the skybox and weather of the level, effectively increasing the variety of maps even more (Skybox variations noted in italics).
In addition to the four base game maps, three additional maps were added into the game for free via content updates.