Welcome to my civilization concept post.
Disclaimer: First of all, im not part of aoe2 team so im not an expert balancing civs, please don’t take it seriously as it’s just a suggestion. Some ideas might sound broken and unbalanced but I wanted to increase the variety of civs by making them more original. 
Introduction: Sioux, broad alliance of North American Indian peoples who spoke three related languages within the Siouan language family. The name Sioux is an abbreviation of Nadouessioux (“Adders”; i.e., enemies), a name originally applied to them by the Ojibwa.
The Sioux way of life
Before the middle of the 17th century, the Santee Sioux lived in the area around Lake Superior, where they gathered wild rice and other foods, hunted deer and buffalo, and speared fish from canoes. Prolonged and continual warfare with the Ojibwa to their east drove the Santee into what is now southern and western Minnesota, at that time the territory of the agricultural Teton and Yankton. In turn, the Santee forced these two groups from Minnesota into what are now North and South Dakota. Horses were becoming common on the Plains during this period, and the Teton and Yankton abandoned agriculture in favour of an economy centred on the nomadic hunting of bison.
Precontact Sioux culture
Sioux men acquired status by performing brave deeds in warfare; horses and scalps obtained in a raid were evidence of valour. Sioux women were skilled at porcupine-quill and bead embroidery, favouring geometric designs; they also produced prodigious numbers of processed bison hides during the 19th century, when the trade value of these “buffalo robes” increased dramatically. Community policing was performed by men’s military societies, the most significant duty of which was to oversee the buffalo hunt. Women’s societies generally focused on fertility, healing, and the overall well-being of the group. Other societies focused on ritual dance and shamanism.
Sioux warriors used bows and arrows, spears, war clubs, and buffalo-hide shields. Hunters also used snares, and when Lakota or Dakota men hunted buffalo, they often set controlled fires to herd the animals into traps or over cliffs.
Sioux women are known for their decorative embroidery with beads and porcupine quills, and the men are known for their elaborate buffalo-hide paintings. Sioux artists also make clay pots, star quilt blankets, and ceremonial calumets (pipes carved from catlinite.)
The Sioux traded regularly with other tribes of the Great Plains. They particularly liked to trade buffalo hides and meat to farming tribes like the Arikara in exchange for corn. These tribes usually communicated using sign language.
The Sioux also fought wars with other tribes. Plains Indian tribes treated war differently than European countries did. They didn’t fight over territory but instead to prove their courage, and so Plains Indian war parties rarely fought to the death or destroyed each other’s villages. Instead, their war customs included counting coup (touching an opponent in battle without harming him), stealing an enemy’s weapon or horse, or forcing the other tribe’s warriors to retreat. Some tribes the Sioux frequently fought with included the Assiniboine, Ojibwa, and Kiowa Indians.
Sioux architecture:
Their arquitecture will be a new north american style composed of teepees and buildings made of wood and animal skin.Their wonder will be a big teepee, because of their lifestyle they didn’t create big buildingsor cities like the Mongols.
So after this small introduction let’s start with the civ concept.
-The Sioux-
Cavalry civilization.
Civilization bonuses:
-Houses, towers and stables are built faster (improving each age).
-Villagers slowly get gold in adition to food.(from animals and berries only. Does not include fish)
-Cavalry units recover hp over time and move faster when close to the enemy. (increasing from the feudal age)
-Gets one free bison for each tech researched.(Spawns 1 in all existing town centers)
Unique units:
-Kanya Horseman: Replaces knight line. Melee heavy cavalry, strong vs buildings, archers and infantry, weak vs monks and pikemen. Can be upgraded to elite in the imperial age.
-Bow rider: Can be trained in castles. Unique mounted archer, cheap and fast. Strong vs infantry, siege and cavalry (after researching the tech) and weak vs archers and squirmishers. Can be upgraded to elite in the imperial age.
Unique techs:
-Castle age- Horse Secrets: cavalry units and bow riders deal bonus damage to other cavalry and siege.
-Imperial age- Bonepipe Armor; Rams have more hit points and melee armor.
Team bonus: The area around your town center will be explored at the start of the game.(It’s like exploring the area around your tc to find resources but u can’t see if the enemy is there.)
Tech tree:
-barracks: (average) full tech except halbs.
-Stable: (excelent) full tech except knight line, steppe lancers,elephants,…
-Archery ranges:(below average) Missing arbalest, hand cannons, cav archers and parthian tactics.
-Siege workshop: (mediocre) Only available ram line and mangonel (no onagers).
-Blacksmith: missing last archer armor.
-Economy: all upgrades except crop rotation.
-Dock:(Below average) Missing dry dock, shipwright, heavy demo, cannon galleon and fast fire ship.
-Monastery: (excelent) all techs.
