Assembly

Assembly (formerly known as Purple Reign) is a Halo 3 multiplayer map which is part of the Mythic Map Pack which additionally includes Orbital, and Sandbox. It was originally planned to be in the Heroic Map Pack, then the Legendary Map Pack, but was replaced due to the fear that it wouldn't be finished on time. This map Assembly along with Sandbox and Orbital was released February 27- March 3, 2009, depending on world region, with Halo Wars LCE.

Design
The map is based inside a Covenant Scarab factory. When looking overhead, legless Scarabs can be seen moving by some kind of automated gravity beam. As such, the area outside the level is immense.

The map itself is bowl shaped, sloping toward the center. This bottom floor is dotted with pillars and walls for cover. It has an outer rim with four bridges, that connect to the two-story center structure, and has small structures on the rim intended as high ground. The bases are symmetrical, but the level actually has two distinct sides, with a lift on one side and what we refer to as the "dugout" on the other, making side differentiation that much better. Line of sight is generally open, with mid-range combat being optimal when on the second level. However, within the center structure and around the pillars that dot the bottom level, close combat is possible.

The map is focused on competitive playing, as it is a multi-story arena-style map. It features two "somewhat enclosed" bases, with one-way mirrors on the second floor (like those in interrogation rooms), where players will be able to look out, but players outside will be unable to see in.

Mystery
Before Assembly was removed from the Legendary Map Pack, it was stated that one of the maps would expand upon the Scarab-Hunter mystery. In a recent Weekly Update, it was stated that, "One base of this open-air arena could end up getting called 'Energy side' and another call-out could end up 'Hunter side'", so it's possible that this was the map they were referring to.

Adding to this mystery, Luke Smith posted on a thread on the Bungie forums that "the name Assembly is extremely appropriate." It would be found that this comment, came after the release of the name of the map in the Weekly Update on the same day. His comment would refer the fact that Scarabs are assembled within the facility. The Scarabs are carried along an assembly line, with the playable area of the map being one of the machines that constructs the Scarabs.

It was revealed that like the Hunters are made of many Lekgolo Worms joined together, a Scarab tank is a whole colony joined together.

Skull
The crest of the hidden Skull on this map appears to be what looks like that of the Lekgolo worms referring to the Scarab assembly line in the distance.

Trivia

 * In the images, fog can be seen in the distance if you are far enough away from a structure. Similar fog can be seen on the Halo 2 level High Charity near in the parts with Flood though with likely different origins from one another.
 * The codename name of the map, Purple Reign, could have been a homonym with the TNT firework "Purple Rain", it could also be linked as a tongue in cheek reference to the song "Purple Rain" from the artist Prince, but it is most likely referring to the dominance of the color purple on the map.
 * Although not a true screen shot, a pen rendering of the map was featured in the Bungie Weekly Update on July 25, 2008.
 * A Bungie Weekly Update has released several screenshots for those who are unable to reach PAX 2008.
 * You can get the Hammer Time Achievement for getting 5 Hammer kills on this map.
 * It has been confirmed by Game Informer that the pilots of the Scarabs are the Lekgolo worms which make up the Hunters.
 * In one of the bases, individual Lekgolo worms can be seen in tubes filled with a yellow liquid.