Maybe a little background is in order. The genre that the series Untamed belongs to is known in Chinese as 仙侠,which is kind of like Wuxia, but with an added magical element, so that the characters may have certain super natural powers, or can acquire them by following esoteric or occult practices. The seat of this occult power manifest itself in body as the "金丹", which Netflixs translated quite literally as the "golden core". When the golden core is gone or removed the supernatural power goes with it as well. This becomes an important plot point later, and since this idea of a golden core is quite common and requires no explanation to the Chinese, the series itself will not have any attempt at any exposition. Think of it as wuxia meets harry potter.
In The Untamed, most people do not have supernatural powers. Those who do possess the power are called 仙,which I would translate in this context as semi-immortals, not demi-gods as the dictionary would have it, and they mostly belong to one of the five major clans, though with some exceptions here and there. They are regarded with great awe and admiration by ordinary folks. When the series opens, the family where Wei Wuxian finds himselve revived from the dead, is actually a hanger on to the wealthy and powerful Jin clan, by virtue of the second son being a bastard of the womenizing clan leader Jin Guangshan.
This large cast of characters and the relationship between them and the clans are what make the series quite confusing initially, especially for people who haven't read the books. So I'll start with a little explanation of the five clans. For easy of memory each correspond to one of the five elements, it's not really relevent to the plot, but it is very relevent to the aesthetics the series. It is also somewhat useful for figuring out who's who, as each clan dressed in their clan's colors.
Let me cover the two clans of the main characters, Jiang clan of Yunmeng, and Lan clan of Gusu.
First we start with the Jiang Clan of Yu Jiang Clan of Yunmeng, 云梦江氏. Wei Wuxian's clan. The name of their home is evocative in of itself - cloud dream. The last name, meaning river, also hints at their roots. Their symbol is the 9 petaled lotus, and their element is water. With exception of Wei Wuxian, they are mostly dressed in shades of lavender, purple, shading into indigo and periwinkle. The colors used are the colors of the Jiangnan, of lakes with miles upon miles of lotus, the water shading into the sky. It is said that the founder of the Jiang Clan was a wanderer and a traveler, and unlike the other clans with their scriptures and three thousand rules, the Jiang Clan has only a single motto, "know what can not be done yet do it".
Wei Wuxian (魏无羡)occupies an awkward place in this clan. Officially he is the adopted son of the clan leader, Jiang Fengmian, and treated as his own. If anything, he seems to be preferred by Jiang Fengmian to the actual son and heir, Jiang Cheng, as Wei Wuxian seems in everyway to fit the ideal of the clan, free, fearless, and unfettered by normal rules or mundan concerns. However, Wei Wuxian is actually the son of Jiang's majordomo, and thus in this very hierarchal world, he is the son of a servant, and thus really never the equal of his adopted brother. Jiang Cheng appears to have absorbed this way of thinking from his mother, who obviously dislikes Wei Wuxian, especially as it was rumored that her husband was actually in love with Wei Wuxian's mother. As the series progresses, Jiang Cheng becomes increasingly torn between his fondness and admiration for Wei Wuxian, and at the same time his sense of his superiority to a servant's son. The heart of the family is actually the older sister, Jiang Yanli, who in spite of her lack of supernatural powers is the one person who holds the family together.

Lan Wangji belongs to the Lan clan of Gusu. Gusu is the name of the region, while the actual name of their estate is 云深不知处 - hidden place in the cloud. Their symbol is naturally the cloud, and the element they correspond to is air. The clan leader is Lan Qiren, Lan Wangji and his brother's uncle. Their father was in a hidden retreat, for reasons which will be explaned much later. The Lan clan also have the unique power of embeduing music with supernatural power. Lan Yichen's reed, and Lan Wangji's zither, are both capable of summoning the dead as well as turning the living to the dead.
The Lan clan is the most rigorous and strict of all the clans, famous for their three thousand rules which all their disciples have to memorize and recite. They are considered the exemplar of righteous behavior among the clans, and and every year each of the clans send their scions to the Lan clan to be schooled in the supernatural arts, which is where the flashback sequence starts. Lan Wangji and his older brother, Lan Yichen, often called the twin jewels of Gusu, are upheld as the examplar of examplar. Lan Wangji in particular appears at the beginning of the series as that perfect known it all whom everyone loves to hates, but Wei Wuxian's presence turns his perfectly order life upside down.
