Even outside of Genshin Impact's main quest line – perhaps particularly outside of it – a great deal about the world of Teyvat can be inferred from certain landmarks or hints dropped in dialogue.
Liyue's highlands are rife with narrative bread crumbs to follow, although some might require exploring outside of the main questline. Here are five side quests to complete to learn more about Genshin's ancient China analog. Spoilers are unavoidable but kept nonspecific.
10 Completing: A Lone Ship In Guyun
See the giant, golden vessel in Liyue Harbor? That's not the eponymous ship. Look behind that party boat, to the precipice of the game's render distance, to see an even bigger pirate ship sporting red sails.
This is the Alcor that is accessible from the Guyun Stone Forest. Don't drown trying to swim there, instead climb the mountain above the most south-eastern domain and glide from the top. Once aboard, the crew won't be pleased by your dramatic entrance, but finishing some errands for them is a sufficient olive branch. You'll just need some common items like meat, fowl, and starconches.
9 What's revealed: A Lone Ship In Guyun
Beidou-mains already know about the Alcor, and the wider Crux fleet, from her friendship lines because the renowned swashbuckler is the leader of both. Beidou is described as the second or third most famous woman in Liyue, outshone only by the Qixing. Gallant tales shared by her crew built her reputation as the local Jack Sparrow or Robin Hood amalgam.
The shipmates mention returning from Inazuma, the Japan-inspired isolationist nation of the Electro Archon that'll likely feature in the March expansion. Travel to Inazuma is strictly prohibited but Beidou is never too concerned with laws, expect her and the Crux to aid in your travels soon.
8 Completing: The Yaksha's Wish
Find the waypoint above the "t" of "Jueyun Karst" on the map. Travel eastwards to a collapsed rotunda-like structure. There's a bejeweled pedestal channeling the spirit of a yaksha named Bosacius, who wishes to pass away but not before bequeathing his riches.
Retrieve treasures from some mages immediately to the east, a lawachurl to the north, and a ruin guard to the south, and then return to Bosacius to unlock the nearby tomb housing three precious chests.
7 What's revealed: The Yaksha's Wish
Bosacius' parting words tell of The Great Yakshas, fearsome adepti (read: demigods) who served the Geo God, Rex Lapis. Although all adepti are highly revered, Bosacius describes the yakshas' work as shameful, perhaps because it involved hunting other adepti, gods, or humans from competing nations.
The yakshas – just like the archons and other gods – are not immortal, nor infallible, and may feel remorse for their roles in the political conflicts that scarred Teyvat. With Bosacius's death, one of the five yakshas remains, Alatus, better known by his alias Xaio.
6 Completing: Nine Pillars of Peace
Beneath the "Cuijue" in "Cuijue Slope" is a marshy lakebed. Traveling there will always trigger dense, ominous clouds. You'll notice nine glowing obelisks framing the lakebed and a stone epitaph in the center.
Collect 130 geoculus either using the oculus tracker or by following an online guide. Power up your Geo statues using the oculi to receive Stones of Remembrance. Place each stone atop an obelisk to gain passage into a crypt. Inside you'll face arguably the toughest fight in any side quest. Winning the battle awards a "dull ring" item that you'll have to sell upon turning in the quest, as well as other valuable loot.
5 What's revealed: Nine Pillars of Peace
The tablet states that the obelisks were constructed to "end the conflicts that plague this world." Presumably, the obelisks were placed following The Archon War and, given their location and shape, they were likely placed by Rex Lapis, aka Zhong Li. Toppling the obelisks is an omen of more war to come, so these probably weren't placed before the Archon War, unless that conflict erupted regardless of the pillars' positions 2,000 years ago.
But why are there enemies in a crypt that's been sealed for millennia? Opening the crypt isn't an act of defilement and you're rewarded for doing so with pricey loot. It seems then that the battle inside is designed to test the mettle of those determined enough to unlock the gate, rather than as a deterrent. Perhaps the whole "Pillars" quest was one of Rex Lapis' plots for assessing the strength of humans before abdicating his throne and passing on his responsibility as a steward of peace.
4 Completing: The Chi of Guyun
As this quest has a lot of steps, here's a general summary. The nearest waypoint south of Wuwang Hill is nestled among ruins, speak to Yan'er there to begin. You'll find a Ruin Hunter in the area and a note instructing you to activate three statues in the vicinity, the large amber chunks indicate the statues' locations.
Find Granny Ruoxin near the last "e" in "Qingce Village." She'll tell you to retrieve fragments of a stone tablet illustrating the resting place of the Chi. Find an altar near the "Q" in "Qingce Village" and activate the statues according to the direction they face: N, SE, NW, NE, and SW. Then climb the tallest mountain in Qingce, right behind Granny, and activate those statues according to the landmarks they face. Return to Granny with the fragments, she'll tell you that they depict a tomb behind a waterfall northwest of the village. You'll fight some treasure hoarders there, then complete a torch puzzle to open the tomb for a formidable battle – you may want an archer for head-shots/stuns – that rewards you with six chests.
3 What's revealed: The Chi of Guyun
This mission is a mess lore-wise. The "Chi of Guyun" quest never leads to Guyun Stone Forest, which is in the sea southeast of Liyue. Instead, you'll explore Qingce Village, which is inland and far north. This has caused players to confuse the Chi with the sea monster Osial. You're told that Qingce's (pronounced: Chin-seh) name is derived from "Chi," who used to rule from the mountain there, and that the terraces in the village were built on the scales of the felled dragon once Rex Lapis ended its terrible reign. So why the "of Guyun" title?
This quest tells you a lot, but much of the info is contradictory. Hopefully, a future update better details the Chi's fate. This quest does reveal something about treasure hoarders though. The waterfall mob drops a journal that says they're waiting for their boss, an unknown woman, to open the tomb. Female hoarders have been seen in trailers, but never properly in-game, perhaps the female hoarder model has been repurposed for a character with a more significant role.
2 Completing: Treasure Lost, Treasure Found
Another journey of many steps, but none very complicated, you can even skip most of the fights.
Step one: find Soraya near the ruins just south of the Guili Plains domain. Find five tablets in the ruins, which are patrolled by some lightweight mobs, and return to tell Soraya the inscriptions on them. The tablets are sizeable and all around the cube-shaped ruin, they're easy to find.
Step two: Soraya will ask you to find two more tablets, one is inside the next closest ruin to the southwest, use the waypoint to travel there. The other tablet is in a valley just east of Luhua Pool.
Step three: visit Soraya at Wangshu Inn. You'll have to find more ruins now with vague directions. You're looking for small, rounded pedestals there. The first ruin is easy to miss, but just a short glide south from Wangshu. Next, warp to the waypoint east of Luhua pool and cross the broken bridge to the north. The third pedestal is northeast of the domain you warped to for step one. Finally, go back to the waypoint you used to find the first tablet in step two, glide north briefly for that pedestal.
Step four: find one final pedestal in front of the large well northwest of the Guili domain, defeat the mini-bosses to drain the well and claim your treasures.
1 What's revealed: Treasure Lost, Treasure Found
The first tablets tell of the Goddess Guizhong, ruler over salt. She defended the plains with Zhong Li, the "Guili "moniker being a portmanteau of their names. During The Archon War, the seven elemental archons and other competing gods had yet to form a peace treaty and were hostile to one another. This makes the union between Guizhong and Zhong Li quite exceptional.
Guizhong was said to be the more empathetic, almost human, of the two – whereas Zhong Li was more brutish – hence her four commandments serving as moral directives for her people. Through some unknown treachery, Guizhong was killed and her villages razed, forcing her surviving followers to settle Liyue Harbor with Zhong Li's guidance. Reddit user tzitzimeme has inferred even more about the befallen deity in a lengthy post that's well worth the read.