With every new Genshin Impact update, we get new characters in the game, and to ascend them, we need to farm their ascension materials. One of them is the Evergroom Ring which is an ascension material required to ascend Baizhu.
As per the in-game description, "A mystical weapon obtained after defeating the four-limbed envoy of dark tidings." Here is where you can farm Evergroom Ring in Genshin Impact and a guide to doing it easily.
Genshin Impact Evergroom Ring: How To Farm
As mentioned above, you will have to defeat the four-limbed envoy of dark tidings, which is Iniquitous Lustrators, the new boss enemy coming to the Genshin Impact 3.6 update, in order to get Evergroom Ring.

Since the update hasn't been released yet, we don't know the exact location of this boss. However, you will be able to find him in the new area coming with the update, which is called Lenerock Desert and Waftgoal.
As per Iniquitous Lustrators leaks, he is "a monster from the Abyss that wields multiple types of Elemental Power and has gained extra limbs from its 'evolution'." We will update this page once we get more information about it, including its location, tips to beat it easily, and more.