The Genshin Impact manga pre-dates the videogame by quite a bit, and as a result of this many minor details were changed in the final product like names (the Knights of Favonius for example were called Ordo Favonius), characters clothes and so on.
So far the manga has been more explicit than the game in showing the nature of certain factions/characters. The Fatui mostly, but not limited just to them.
- Fatui have an underground arena where they conduct experiments on living begins.
- They forcibly enlist people from other nations to be used as guinea pigs.
- based on the plot they seem to be targeting young people specifically (a younger Diluc calls the missing person a "boy") - ties to the "faster aging" effect Delusions seems to cause - Kaeya is probably fully aware of the thing and so are the Knights.
- Venti being told how the Lawrence clan son twisted the Harpestrum rite.
and so on...
Yet, so far the game doesn't seem to have really made any of this very explicit outside some minor details like:
mentioning Dottore's research in Childe's quest and the Delusions effects like faster aging during Inazuma arc.
Sometimes characters seem to omit info that you would think they would mention:
For example at least Diluc and Kaeya are clearly both aware that the Fatui are murdering people "for research" but neither of them tell that to the Traveler even when the opportunity arises. This seems quite out of character. Had the traveler been aware of such info their meeting with Childe would likely have gone quite differently.
At the same time, the game does indeed reference the manga multiple times. For example:
- Collei is referenced in Mondstadt.
- the "odd vase" in Diluc's house is clearly meant to be the one Kaeya promised to buy and later actually delivered to him
The question is therefore simple. Is there any indication if the lore darker elements are still canon or have been retconned for the game to have a lower age rating?
As a comparison, the original intro to the game used during the initial beta was a lot darker, and some parts of it seems to have been changed in the final release.