This page uses terminology coined by the translator, RainbowSe7en (except for the Awl of Mountains and Rivers).
This page contains spoilers for the whole novel.
The story is divided into four arcs, each one deals with a mystical artifact:
Sundial of Reincarnation[]
轮回晷 Lúnhuí Guǐ (轮 lún = wheel, 回 huí = to revolve, 轮回 lúnhuí = reincarnation, 晷 guǐ = sundial)
The Sundial of Reincarnation can transfer life force from one person to another. The novel is very clear on the fact that to prolong one person's life, the exact same amount of time has to be subtracted from the other person's life. Essentially, their combined remaining life time is split equally between the two. (reference needed)
Awl of Mountains and Rivers[]
山河锥 Shānhé Zhuī (山 shān = mountain, 河 hé = river, 锥 zhuī = cone, awl)
The Awl of Mountains and Rivers is an ancient natural artifact that was placed between heaven and hell and can stop ghosts from traveling between them. It is inscribed with laws.
Zhao Yunlan discovers the Awl of Mountains and Rivers in chapter 36 (TODO).
It is "a colossal stone monument, several dozens meters tall, towering from the Earth into the Heavens. It is entirely black, thicker at the top and thinner at the bottom, like a gigantic wedge nailed into the ground. At the bottom is a ruined ritual site."
The Ghost Slayer explains the history of the Awl in chapter 37:
"People often say 'the gods and the spirits control Life and Death', but that's not true. Ever since the dawn of time, there were Good and Evil. The earliest judgment was engraved onto the Awl of Mountains and Rivers, to tell Good from Evil. This great pillar was formed from a million mountain and river spirits, and it extends from the Nine Heavens down to the depths of the Underworld. On it are written the details of all Eighteen Levels of Hell, and the Book of Life and Death comes from the judgment engraved upon it. Ever since the creation of the awl, people believed that the mountains and rivers have their spirits."
"The Awl of Mountains and Rivers was first created to suppress ghosts. Over time, millions of evil spirits have ended up imprisoned within it."
The Hanga tribe used it to trap their own deceased tribe members' ghosts in it and control them using their skulls.
The Awl can only trap souls whose bodies are no longer intact.
Zhao Yunlan hears the souls inside the awl scream, and it causes so much pressure in his chest that he cannot breathe anymore, starts vomiting blood, and almost dies (chapter 36 (TODO)). The Ghost Slayer explains (probably facetiously) that Zhao Yunlan was "born with an unstable soul. A human has Samadhi true fire in three places: head and both shoulders. [His] left shoulder is missing a fire." This is true but probably not the explanation for why the Awl affects him this much.
Ink Brush of Virtue[]
功德笔 Gōngdé Bǐ (功 gōng = merit, 德 dé = virtue, 笔 bǐ = pen,brush)
The Ink Brush of Virtue is said to be carved from "the root of a tree that grows in Hell." Its wood is "indestructible, unbreakable by blades," and it bears no leaves, flowers, or fruit.
It is called the "Primeval Tree of Virtue." (chapter 56)
Shen Wei thinks that the naming of this "not yet lived but dead" tree turns the very concept of virtue and karma upside down, because it inverts the intention of "doing good to gain virtue and eschewing evil for fear of karma," and thus precludes the emergence of true virtue.
It can write "black for evil and red for good, one on the left and one on the right, whether you're a boon or a bane, a villain or a hero, it does not matter." The brush can overwrite anything and turn evil people into seemingly good ones (and presumably vice-versa). (chapter 56)
Lantern of the Guardian[]
镇魂灯 Zhènhún Dēng (镇魂 zhènhún = translated as "Guardian" in the context of the novel, 灯 dēng = lamp)
The Lantern of the Guardian was made by the god Kunlun from pieces of himself. (reference TODO)
It's now placed (in infinite copies) along the path through the Underworld, etched with the phrase "True Death Begets New Life". The Lanterns are supposed to guide souls towards the River of Forgetfulness. Their light will clean them, so they can start a new cycle of reincarnation. The length of the road depends on how many things the dying soul has to forget. The river itself is part of Chinese mythology, but the Lantern is an addition by Priest. (chapter 83)