Genshin Impact introduced Khaenri'ah as far back as the Teyvat Chapter Preview: Travail video in 2020. As the game progressed, it showed off the nation as highly advanced, both technologically and in terms of alchemy, with it being most known for its collapse during the infamous Cataclysm. Given the implication in that same chapter preview that Travelers will eventually be given the chance to explore the nation of Khaenri'ah, there's quite a bit to uncover about it.
It will be a while before players get the chance to see the nation, whether it's brought back to prosperity by the Abyss sibling (as stated in the Traveler quest, "Requiem of the Echoing Depths," this is their goal) or if players explore the ruins of the old world. The old world has been teased and hinted at throughout numerous important points in the story, such as the Interlude chapters that Genshin Impact has put in-game for players to enjoy.
Despite being a ruined nation, there are people who are either from Khaenri'ah, have ties to Khaenri'ah, or are related to people from the nation. Some of the most known characters with Khaenri'ahn ties are Genshin Impact's Albedo, Kaeya, and Dainsleif. In order, these connections are:
Rhinedottir, also commonly referred to as Gold in the Genshin Impact lore. She is notorious for her practice of Khemia, a form of alchemy that allows its practitioners to create false lifeforms. She created the Genshin Impact enemy Rifthounds, Albedo, the false Albedos, and the old dragon named Durin who died in Dragonspine. This practice is largely what is blamed for the collapse of the nation.
The underground nation of Khaenri'ah was most known for its alchemical achievements due to Rhinedottir's experiments. Beyond this, the people of Khaenri'ah also created the Genshin Impact Ruin Guard enemies seen scattered across the map. Their original names for these war machines were "Field Tillers." After the downfall of the nation, they spread out across Teyvat. However, it is also likely that the Fatui are making these robots on their own, as implied in Childe's Story Quest where players entered one of the Doctor's abandoned labs.
The old world was the only nation without a god at its helm. Every other nation worshiped a Genshin Impact Archon or deity, but here, they remained under their own rule. They had a royal family at its helm with a ruler known as King Irmin. This ruler was also said to have introduced forbidden knowledge into the nation to help push the advancements being made at the time. This tied into a lot of different assets of the kingdom, including both Ruin Guard creation and Khemia under Rhinedottir's careful gaze.
When Rhinedottir's creations escaped and began terrorizing not just Khaenri'ah, but all of Teyvat, that is when Celestia and most of the Archons intervened. The only one not to participate was Greater Lord Rukkhadevata, who had to protect Irminsul. The gods tore the land apart and cursed the people of Khaenri'ah. Those who were "pure-blooded" would be cursed with immortality, while those who were not were turned into monsters such as Genshin Impact's Hilichurls. Not only was the nation destroyed during this event, the Cataclysm, but two of the six Archons who were involved also passed away: Raiden Makoto and Egeria.
Genshin Impact is an open-world RPG made by MiHoYo. Focusing on the interactions between seven elements, Genshin Impact is a free-to-play gacha game with a host of characters, weapons, regions, and more.