The Red Lotus was an offshoot of its White counterpart — it consisted of Zaheer, P'Li, Ming-hua, and Ghazan, who were the main antagonists in Book 3: Changes of The Legend of Korra. Though a secret group, they weren't really private about wanting to abduct the Avatar, which they tried to do but failed (at least on their first attempt).
Zaheer claims that The Red Lotus exists to right the wrongs of its parent organization, but their core philosophy revolves around the element of chaos, or anarchy, which is an unnecessary complication in an otherwise harmonious world. When were they founded? What did their actions influence?
10 Founded Shortly After The Hundred Year War
The Order of the White Lotus chose to side with the Avatar and the decisions he made regarding the future of the world, which infuriated one of its top members, Xai Bau.
He claimed that the original organization had been practically demoted into being Aang's "bodyguards", and therefore decided to establish a splinter sect consisting of others who believed in his version of the narrative. He called it the Red Lotus, indirectly referring to the bloody means they were willing to take in order to accomplish their goals.
9 The White Lotus Was Aware Of This Cult
At first, the White Lotus maintained complete knowledge of this new group's motivations, philosophies, and activities, spurred on by Iroh, the Grand Lotus, who took a cautionary stance regarding the Red Lotus.
However, this means that Xai Bau and his new followers were free to recruit as many "dissidents" as they wished, thereby swelling their numbers even further. In fact, even after the Red Lotus openly declared their mission to establish anarchy (by destroying the very concepts of countries and political structures), the White Lotus remained impassive.
8 Grand Lotus Iroh Failed In Controlling Them
Iroh tried his best to preserve the balance between the two opposing factions, desperately hoping that the Red Lotus might reconsider their implausible goals.
Iroh knew that they would end up causing a lot of destruction in the future if they weren't nipped in the bud, and yet he did nothing except pray that the two groups might one day return as one. If he had taken decisive action, rather than hinge his bets on the goodness of people's hearts, the Red Lotus wouldn't have had the chance to do what they did to Korra.
7 It Takes A Powerful Team To Stop Them (The First Time)
The Red Lotus in Avatar Korra's time consisted of Zaheer, P'Li, Ming-Hua, Ghazan, and Unalaq, all of whom formulated a scheme to destroy the Avatar reincarnation cycle forever by killing Korra in the Avatar State.
Thankfully, the combined efforts of Sokka, Tonraq, Zuko, and Tenzin were enough to defeat them, although it must be stated that Zaheer did not possess his Airbending skills at the time. The four main antagonists were later separated and imprisoned in locations contrary to their bending styles.
6 They Are Betrayed By Unalaq
Unalaq isn't captured along with the others because he conveniently did not accompany the Red Lotus on their Korra-abduction outing, and pretended that he had no idea what they were talking about when they tried to rat him out.
This was the only way for him to avoid the destruction of his own secret plans (to release Vaatu, fuse with him as Wan had with Raava, and turn into the Dark Avatar). What Unalaq wanted to do as the Dark Avatar is anyone's guess. He probably just wanted to run around ruining things for everyone.
5 The Red Lotus Has More Than Four Members
In addition to Ming-Hua, Zaheer, Ghazan, P'Li, and Unalaq, the Red Lotus included Aiwei (Suyin Beifong's adviser for all political matters concerning the city of Zaofu). Also, when they attempted to inject mercury into Korra's veins, several other minions were observed holding vessels containing the toxic liquid.
This implies that the Red Lotus isn't as small as it seems, and may well have a large number of members still remaining around the world, biding their time for an opportune moment.
4 They Are Directly Responsible For Kuvira's Rise
The Red Lotus — Zaheer, to be specific — were responsible for the death of Hou Ting, the Earth Queen of Ba Sing Se, who was cruelly suffocated with the help of Airbending (a gross misuse of this gentle style). Almost immediately after the announcement, the city began to riot, and the notions of power and authority were flipped on their heads.
For instance, one of the palace guards doesn't try to stop the looters, he just joins them. This event is directly related to the fragmentation of the Earth Kingdom, which Kuvira then went on to unite under her banner.
3 The United Republic Has Officially Declared Them Terrorists
This is an unsurprising fact, but an important one nevertheless. The Red Lotus, due to their prior endeavor, had been labeled a band of terrorists by most world authorities, including the Fire Nation, Water Tribes, and the Earth Kingdom.
After their semi-successful second try, President Raiko officially proclaimed the Red Lotus to be a terrorist organization, further stating that the United Republic of Nations would do everything in its power to prevent such a thing from happening again.
2 They Also Include Foot Soldiers
Given its status as a rather well-equipped institution, replete with some fine management skills, the Red Lotus presumably hired a decent number of underlings to perform menial jobs.
These included infantrymen, or foot soldiers, two of whom are observed keeping an eye on the Airbender prisoners held at the Red Lotus hideout (snugly built into the side of a massive hill). It's clear that their job is merely perfunctory, however, seeing as they are relegated to boring guard duties, which they can barely even fulfill.
1 The Red Lotus Technically Succeeded In Their Mission
Zaheer revealed that the role of the Red Lotus is to return the world to its true state, chaos, in which there is no order or balance. He believed that only this way will people be free enough to make the choices they want, rather than having them made for them by a government or a monarch.
Anarchy, unfortunately, has a way of getting away from the original intention of its creators, as Zaheer admitted in Book Four: Balance, expressing his guilt over the messed-up state of the world to Korra. Luckily, everyone came together to restore harmony once again, but it happened at an unnecessarily high cost.