Crusader Kings II: Good Job High Chief Piast, 10/10 A+

What is Crusader Kings?

Basically, it's a "grand strategy" game - that is, strategy on a macro level: rather than having individual units assault single cities or fortresses, as in a game like Civilization, you have armies numbering thousands of troops taking down as many as a hundred holdings in a larger war. As a result, it's a lot more abstract than more micro-level strategy games.

But the main draw isn't so much the strategic depth of combat, as much as it is the way the world unfolds. The game is set in a more-or-less historically accurate facsimile of Europe, and simulates a shitton of characters, all of whom have a different opinion of everyone else. A lot of these will never come into play - it doesn't matter too much what the Mongol hordes think of an Irish count, for instance - but at other times, frantically appeasing (or plotting against) vassals and rivals is critical to success. Each character also has unique traits, often of a diametrically opposed pair (such as Attractive/Ugly, Content/Ambitious, Hedonist, Berserker, and so forth), as well as five stats: Diplomacy (self-explanatory), Martial (fighty skills, mainly useful for generals), Stewardship (how good you are at administrative stuff, which affects taxation and how many places you can rule directly), Intrigue (plotting against others while not being plotted against), and Learning (which affects the rate of technological progress).

The other major thing to note is that succession plays a huge part. Rather than having a nonspecific ruler, or playing as the same ruler for the entirety of the game, people die in CKII. When they do, their titles get passed on to an heir chosen in a variety of ways - traditional "oldest son wins out, oldest daughter if there's nobody else around," an opposite version where the youngest child wins big, division of titles between all the ruler's children, passing on the titles to the oldest member of the dynasty as a whole, or elections. This means that titles can be gained not just through indiscriminate warfare, but - as happened historically - by tactful marriages (though, generally, you can only marry those of the same religion as you). The main goal of the game is to make your dynasty as glorious as possible - and if your ruler has no heir of his/her own dynasty, it's game over.

Casus Belli

One thing that's crucial to understand when playing CKII is that you can't just wage war with anyone you want; you have to have a specific reason, or casus belli. This can range from "I was close to inheriting this title, but didn't" (Succession Crisis or Press Claim) to "they're a different religion from me!" (Conquest, Holy War, Invasion, or Crusade/Jihad/Great Holy War) to "GET YOUR FUCKING TRADE POSTS OUTTA HERE" (Embargo, Seize Trade Post). Sometimes we'll need to do a little bit of subterfuge to "confirm" that a war is justified before we can rush into it.

LP Notes

All rulers have various traits that affect their abilities and AI decisions; the majority of the decisions I make will be in-character. That is to say, I'll be less likely to take pity on prisoners while playing a Wrathful character, I'll appoint council members solely on merit (rather than considering if they're likely to use their station to murder me) if playing a Trusting character, I'll cool off the constant landgrabs if playing a Kind or Content character, etc.

I'll also leave certain things up to a vote; for example, if I plan to expand but there's several good fronts to wage war on, I'll probably ask you guys. That being said, I think I'll defer to you on what kind of ruler we should play in terms of religion and government type (as well as, if you care, where specifically we should start if we're playing a more widespread religion), so here's what you need to know:

Trade Republics

In addition to traditional monarchs, The Republic DLC also allows you to play as... uh, a republic. Basically, there's five prominent houses in a trade republic, and they jockey with each other over who gets to be the Grand Mayor/Doge/what-have-you. Gameplay is a lot more focused around hoarding money and establishing trade routes (without sacrificing the traditional war-and-marriage stuff), and succession is pretty fun to deal with.

By default, the only trade republics as of the 867 start date are located in the Mediterranean, but with a little fiddling around, I could manage to set one up further to the North or West. I'll let you guys decide whether to play a monarchy or a Republic.

Religions

• Catholics - The big guns of Christianity, who control the vast majority of Western Europe. They're pretty simple; they have a single head of their Religion, the Pope, who can grant divorces, excommunicate people, and give the go-ahead to Invade heathens. Their widespread power base also gives a lot of opportunity for marriage politics (there is basically no circumstance where someone will let their daughter marry an infidel).
  
  Catholics can go with either Free Investiture (ruler picks bishops) or Papal Investiture; bishops pay taxes/give troops to either their ruler or the pope, depending on who they like better, so Catholic rulers had best be pious if they want to rake in the dough. Catholics with sufficient prestige can also set up an Antipope; bishops may pay taxes to that guy (and by extension, the ruler who established him) instead, and he holds a claim to the Papacy (which is mainly interesting because it means a sufficiently powerful ruler can vassalize the Papacy if they press his claim).
  
  
• Orthodox - Mainly present in the Byzantine Empire, the Orthodox religion and Catholicism split in 1054*, having previously been united. While they do have a singular religious head - the Ecumenical Patriarch - they, unlike the Catholics, also have lesser patriarchs who can also grant divorces and excommunicate people (though only the Ecumenical Patriarch can grant the Invasion CB).
  
  The other thing worth noting about Orthodoxy is that - if the Pentarchy (Constantinople, Rome, Alexandria, Jerusalem, and Antioch) is brought under total Orthodox control - the Great Schism will be healed, and Catholicism reduced to an Orthodox heresy. Otherwise, it's pretty much the same as Catholicism.
  
  While this game will be starting in the ninth century, religious tensions had been brewing between East and West for a while, so the Catholic and Orthodox churches being considered separate is a reasonable gameplay abstraction. It's possible that the next expansion - which will refine Christian and Muslim mechanics, as well as adding Judaism to the mix - will change the way the Schism works.
  
  
• Miaphysites - Honestly pretty much just "Orthodox, but less interesting." Due to having much bigger doctrinal differences with the other major Christian sects, they can't heal the Schism if they complete the Pentarchy. This kind of means there's not much point to doing so, since their Holy Sites don't match up with the Pentarchy.
  
  They're mostly based in East Africa, and they're not much less fucked by Islam than the West African pagans are, which might be interesting.
  
  
• Muslims - Shia and Sunni rulers have basically identical mechanics. Their religious heads, the Caliphs, are different from all others - first, they are primarily secular rulers, with the Caliphate being merely one of many titles for them; second, it is possible for either Caliphate to dissolve if no suitable heir exists (and, in fact, the Shia caliphate doesn't exist as of 867), though it can be re-established later.
  
  Muslim rulers are expected to have multiple wives, and have to deal with Decadence, which increases for members of the dynasty with insufficient holdings. As decadence grows, taxation and army morale decrease, and if it's allowed to reach a fever pitch, a rebellion may rise to topple that dynasty and take over as rulers (though vassals can declare independence if they succeed).
  
  Muslims also have the Agnatic Open succession rule at all times - whichever son of the ruler is most powerful gets all of his titles upon succession. Honestly, it's probably one of the best succession laws around unless your chosen heir dies prematurely, due to the level of control it gives you over who inherits.
  
  
• Zoroastrians - A Monotheistic religion at the edge of the Middle East, once the official religion of the Persian Empire but marginalized after a Muslim invasion. They start with no religious head, but if they can retake the Empire, they gain one (and the ruler that does so, as well as all his successors, get pretty heavily rewarded for doing so).
  
  Also, Zoroastrian vassals fucking love it if their ruler has an incestuous marriage. Thankfully, you can take concubines as well to ensure a supply of not-inbred heirs.
  
  
• Pagans - Any of the various polytheistic or animistic religions that are gradually giving way to Islam and Christianity. In addition to being able to conquer or loot any territory adjacent to their own, Pagans can Subjugate each other to massively expand their realm. Attackers of an organized religion also take considerable attrition penalties when in an unreformed pagan holding. Unreformed pagans tend to be stuck with Gavelkind succession (that's the kind where your titles are divided between your kids, and is Very Very Bad for realm stability), though sometimes they can switch to Ultimogeniture (the kind where the youngest kid gets everything).
  
  Historically, paganism in Europe and North Africa was supplanted by monotheism, but here they have the ability to reform, codifying their structure and establishing a High Priesthood similar to the Pope, Patriarch or Caliph. By doing so, they lose a couple abilities, but gain the ability to wage Holy Wars and Great Holy Wars, plus they're much better at conversion. Some subjects will refuse to accept the changes, remaining as heretic Old Pagans, but that tends to die down pretty quickly.
  
  Subsets: Norse (who, as vikings, get to conquer/loot any coastal province and sail down rivers), Tengri (mongols and a couple of other steppe tribes that settle in Eastern Europe) and Super Aztecs (if we run Sunset Invasion) are the Offensive Pagan religions; they get a boost to attacking, but their subjects get antsy if they spend too long without a war. The Defensive Pagan religions are Slavic Pagans and Romuva (who hang out around Eastern Europe; the Slavs considerably outnumber the Romuva, who are confined to Lithuania), Suomenusko (Finland and Russia), and West Africans (who are confined to Mali, and are basically completely fucked by Islam unless they get super lucky); they get a boost to defense and have no obligation to go to war.
  

The Ruler Designer

I should also note that I'm able to change my first ruler's starting Traits and skills as well. The maximum starting age is 50, and the minimum is 16 (with the age cost for every base point in a stat [above 5] being +1). So, in addition to religion and government type, what stats should our ruler focus on and what traits should he (or she) have?

Final Note: The Eastern Hordes and The Sunset Invasion

After a while, the Mongol Hordes will arrive in Eastern Europe and the Middle East. They're extremely powerful, and can wage war that only results in a very short truce. If a strong, united front doesn't stand in their way, they'll pretty much run roughshod over everyone until their Khan dies and the conquest has to stop for a while.

But Paradox Interactive realized that this left Western Europe in a much more comfortable position. So DLC was created that's one part balancing and five parts awesome insanity - the Sunset Invasion, in which a technologically supercharged Aztec Empire comes over to fuck up Western Europe with a tremendous army. I'll leave it up to you guys whether or not to use it - obviously it's ahistorical, but hey, it could be pretty fun.

Any mechanics I haven't touched on, I'll bring up when they become important.