Genshin Impact might be planning to reveal the Abyss Order's higher authority very soon, with the Abyss Herald's introduction.
The information comes from the Twitter user Lumie, who is known for leaks and renders of upcoming characters in Genshin Impact. He shows the giant Abyss Heralds' character model.
Genshin Impact: Renders of Abyss Heralds leaked
As shown in the leaks, the Abyss Herald wears a blue cape with what seems like an inhuman physique. The leaked Herald seems to be of Hydro elemental type, just like Hydro Abyss Mages, and it has a height of 294cm or 9 feet and 7 inches in the game. The below-attached height comparison with Klee shows how tall the Abyss Order's new member will be.
According to the in-game references, the Abyss Herald was mentioned in the latest archon quest named Bough Keeper: Dainsleif. In the quest, Dainsleif came Mondstadt looking for the traces of an Abyss Herald. By the end of the world quest, he could not find any traces of the Herald and had to return empty-handed.
According to Dainsleif's description, Abyss Heralds work under the Abyss Order and command the currently existing Abyss Mages on behalf of their leader in the game. The higher resolution of the leaked renders can be found in the below attachment.
Players can be assured that the Abyss Heralds will now be frequently mentioned in the game with upcoming updates and story quests. However, to witness their regular appearance in the game, players will have to wait. It is speculated that a forthcoming chain of quests will make the relation of khaenri'ah, the Abyss Order, and Dainsleif, with the protagonist/traveler's missing sibling, more clear.
The only information that is known about the other sibling is that he/she is the leader of the Abyss in Genshin Impact.