Sid Meier's Alpha Centauri/The Human Hive

Chairman Sheng-ji Yang

At a Glance:
 * +1 Growth
 * +1 Industry
 * -2 Economy
 * Immune to inefficiency
 * Free Perimeter Defense at every base

If not for the lack of energy, this faction would be all but unstoppable, and as it is, they are far and away the most powerful AI faction, coming out on top of the AI heap in almost every simulation we have ever run. Their Growth and Industry bonuses make for rapid expansion, and their inefficiency immunity makes a massive empire with few to no drawbacks a real possibility. This, combined with their inherent "Citizen's Defense Force" makes them a tough faction to match, and if they happen to also get the Command Nexus (not difficult to imagine, since they start with its requisite tech) and Planetary Transit System (also not too much of a stretch, with active Probe Teams), then the rest of the world stands a good chance of being doomed. An important note about Yang: the immunity to inefficiency ability allows you to run Social Engineering settings which would utterly ruin any other faction in the game. Quite simply, you may freely ignore negative modifiers to efficiency!

Yang, the Builder
First, absolutely no one will be expecting you to play Yang as a Builder, so this will work very much to your advantage, but consider: You can switch over to Police State with impunity, enabling you to control your drones without the need to build any drone control facilities at all, and the addition of a Children's Creche at each base goes a long way in capturing what energy you do generate. Add to that the ability to run Planned (again, without penalty), and you get a faction with a huge industry bonus and no drone problems whatsoever. If you work heavily with forests, your income won't be bad, although you will never even begin to approach the energy levels of the real "Research Factions" in the game, forcing you to look for other alternatives. Fortunately, there are some very good ones, and you get them at the same time you get the ability to run Planned, namely: Librarians. While you're waiting for Industrial Automation, you can be whipping out Network Nodes and expanding like mad, and once you have the ability to create crawlers, it's easy (again, with your prodigious Industry bonus) to crank out enough crawlers to give each base some minerals to work with, and feed the entire population, and once you do that, every citizen you have can be converted to a Librarian, giving you perfectly efficient research capabilities, magnified by your already built network nodes. Now consider that if you take the time to build the Command Nexus, you essentially wipe out the penalties for also running Wealth (adding a bit more to your energy reserves, and giving you yet another boost in Industry). The only person in the game who can out-build you is Domai, and he has to contend with less-well defended bases, efficiency problems, and a research penalty, which more than offsets his additional +1 bonus to Industry. In short, although it might not appear so at first glance, the good Chairman makes an astonishing builder, and that capability, coupled with an active stance with probes will quickly see you on par with every other Builder in the game, should you choose to run the game this way.

Yang, the Hybrid
Again, this approach uses Yang's industrial might, and is not terribly different from his Builder game, except that a certain set of bases will be geared up specifically for the purpose of providing an offensive punch to the empire, whereas the pure Builder approach will not do so until and unless threats begin appearing on the horizon. The Yang-Hybrid model enables you to maintain an active attack/trolling force while keeping a fairly brisk research rate, and the ability to drop into full Builder mode if you determine that your potential enemies are very far away. On the other hand, it's easy (gotta love that Industry) to kick into high gear and get ready to fight, and very quickly, you can find yourself with an army numbering so many units that you can simply sweep the opposition off the map.

Yang, the Conqueror
Once more, your Industry and Police are the key factors to the Conquest game. The goal here is to simply skip over any real Infrastructural builds and focus on rapid colonization, followed by a buildup of troops that no one else in the game can match prior to the arrival of clean reactors. Even Miriam, with her support bonus simply cannot keep up with a fully geared-for-war Yang. So what if she's got better troops, you can replace your losses almost half again as quickly as she can replace hers, and her Probe Immunity is nearly meaningless to you. You likely won't have the cash to do much subversion anyway, and you can simply keep building units until you overwhelm her. Same with the only other truly good fighters in the game, the Spartans, except in their case, it's even easier to overwhelm them, because they have Industrial problems of their own, and the moment you achieve your first conquest on an enemy's soil, that is the kiss of death, as that faction must now deal with your enhanced Industrial output right there on their turf. Simply put, if they do not or cannot re-capture the base immediately, they're doomed.