Raven Software

Raven Software, the creators of the Heretic and Hexen series, have had a long relationship with id Software that began when they liscensed an early alpha of the Doom engine to make Shadowcaster. Now, there has been scarcely a game made by Raven that hasn't used id technology (X-Men Legends, as far as I know, runs on a proprietary engine made in-house at Raven). Raven is now entrusted with the rights to make Quake IV.