Modder ‘Valkyries7331’ has released a cool mod for Doom 3 with the goal of putting the events of Doom 3 in the Halo Universe. What this means is that the mod adds weapons, character models, items, and lore elements from Halo in Doom 3.

For those wondering, this Halo-inspired Mod does not introduce any enemies from Bungie’s titles. Instead, you’ll be fighting your usual cacodemons, lost souls, imps, knights of hell, and all the monsters that are already available in Doom 3.

You can download Doom 3: 2553 from ModDB: https://www.moddb.com/mods/doom-3-2553/downloads/doom-2553-release-v11

Also other Doom 3 mod recommendations from original article https://www.dsogaming.com/pc-performance-analyses/you-can-now-download-a-cool-halo-inspired-mod-for-doom-3/