North Asian civs
In the world of Temüjin, North Asia is by far the richest and most populous part of the known world, and for centuries has been divided into two sections - the frigid and forebodingly less civilised north, consisting of the lands of the Turks and the Tungusic peoples, and the more temperate and more populous lands of China to the south, whose sheer size alone makes North Asia by far the most culturally productive region of all time.
Sadly, this prosperity has earned the envy and covetousness of different nations and tribes and today, the ambitions of one such tribe - the Jurchens - have forged a vast nation covering the southern reaches of the east Asian steppelands, as well as northern China. It would seem thus than the future of China is bound to be dominated solely by the Jurchens - and whoever rules all China, sooner or later becomes lord of all Asia ... and with Asian dominance, the whole world.
Faction highlights
Despite the vast numbers of Wonders available to them, north Asian civs, with the exception of probably Dajin or Minyak, are best used for booming and Wonder rushing. This is especially moreso in the case of Nansong with their complement of five, high WP score monuments, although it could be said that Dajin's economic bonuses and access to fast resource generation upgrades also allows Dajin the ability to boom and seek a unilateral Wonder rush with no alliances.
Military-wise, the heavy cavalry units available to all four nations (or rather five if you include Qara Khitai) have one single trait - they are proficient at countering mounted archers, be they archers firing from horseback, or from the top of a camel or even an elephant. The five heavy cavalry units available to these factions (Heavy Cavalry for Nansong, Gaemamusa for Goryeo, Ordo for Qara Khitai, Tieyaozi for Minyak, Tiefutu for Dajin) are all resistant to cavalry archers (but not javelin cavalry) and can be used to draw enemy horse archers away from your more valuable siege weapons and infantry. However, Qara Khitai's Ordo has one special ability - it is capable of dealing added damage to enemy light and medium cavalry, allowing it to be used in a more offensive manner by chasing down enemy light and medium cavalry (but it is still vulnerable nevertheless to other heavy cavalry units and heavy spears.
Otherwise, these civs all have different foci and play style preferences - with Goryeo and Nansong being mostly defensive, and Minyak Xixia being better geared toward early infantry rushing (particularly since the Minyak do not have advanced siege unit components, so rushing early before the enemy has serious fortifications helps) and Dajin, again, being able to pick different strategies as they see fit. All told, Dajin is clearly the strongest civ, and Goryeo, the weakest.
Wonder pool
Beisita
Shared between Nansong, Dajin.
Confucian Academy
Exclusively for Nansong.
Magnum Horologium
Shared between Nansong, Dajin.
Buddha Grotto Complex
Built in the main by Qara Khitai and Minyak, but also available to Goryeo, Dajin, Nansong and Dai Viet.
Royal Observatory
Shared between all Asian and Muslim factions, excluding Khmer, Minyak and Ayyubids.
Standing Stones