This is Dusted(ingame name: Hecatia)'s Complex Doom addon.
The only requirements are LCA and RM (and of course Complex Doom).


Credits are listed below.

If credits aren't listed for something, that means that I was 
not able to find an author of the specific item (or I'm just lazy).

Tripwire Interactive: Gore Imp, Cerebral Caco, and Cerebral Imp sounds (Killing Floor)
Blizzard: Pain Lord sounds (Diablo)
Nakkemake: Desolator sprites
Vader: Nether Imp and Terror sphere sprites
Damien Daurio: Gore Imp sprites (edited by Dusted)
Neoworm: Chaos Soul sprites (edited by TiberiumSoul)
Ben2k9: Cyber Baron sprites
SunMadCat: Phase Caco sprites (edited by Dusted)
Raven Software: Dark Bishop sprites and sounds (edited by Dusted), Chaos Soul, Desolator, and Spec Ops Zombie sounds (Quake 4)
Freedoom: Dark Bishop death sound
Team Shanghai Alice: Spider Masterspark attack sounds (Touhou)
Ghastly_Dragon: Spec Ops Zombie sprites, Code
Xim: Spec Ops Zombie sprites
Vegeta: Spec Ops Zombie sprites
MagicWazard: Spec Ops Zombie and Salvation sphere sprites
Hacx: Unstability sphere sprites
Eriance: Doom Sphere sprites
Relic Entertainment: Former Admiral sounds (Dawn of War)
Lord Cylarne/Ultimate Apocalypse Team: Legendary Mage and Pain lord sounds (Dawn of War Ultimate Apocalypse mod)
Daedalus: Code
Harbinger: Code
Legendary: Code


Music for the enemies that have them:
Legendary Phase Imp "Audiomachine - There Will Be Blood"
True Legendary Zombie "Audiomachine - Lost Raiders"
Bloody Flandre "AGENT 0 - Bloody Law"
Legendary Archwizard "Dark Souls II OST - Royal Rat Authority"