NieYao

Nieyao is the SLASH ship between Nie Mingjue and Jin Guangyao from the Mo Dao Zu Shi fandom.

Canon
In the novel, Nie Mingjue and Meng Yao meet each other during the Sunshot Campaign, a war that the most prominent clans held against the Wen Clan of Qishan.

Meng Yao's entry into the Nie clan comes after his expulsion from the Golden Carp Tower by his father's guards. This expulsion is a result of Jin Guangshan's refusal to meet his son, in an attempt to avoid his wife's wrath. After this, Meng Yao works as book keeper until the Sunshot Campaign starts. At the outset of the Sunshot Campaign, Meng Yao, with a relatively low-level cultivation, is assigned menial tasks, including cleaning up the battlefield. Despite his caring and respectful demeanor towards his fellow soldiers, he faces ridicule and isolation due to his status as Jin Guangshan's illegitimate son with a prostitute.

Meng Yao endures the hardships of being an outcast, eating alone outside the cave where others gather. One day Nie Mingjue notices the unfair treatment and gossip surrounding Meng Yao. Infuriated by the mistreatment, Nie Mingjue sternly reprimands his subordinates, displaying a sense of justice for Meng Yao. Recognizing Meng Yao's capabilities and character, Nie Mingjue eventually promotes him to be his right-hand man.

Some time after during the Sunshot Campaign, Nie Mingjue overhears a conversation between Meng Yao and Lan Xichen. In this exchange, Lan Xichen inquires about Meng Yao's lingering desire for his father's approval. To Meng Yao's astonishment, Nie Mingjue intervenes, interrupting the conversation to announce that he will write a recommendation letter for Meng Yao immediately the next morning. This turn of events highlights Nie Mingjue's growing regard for Meng Yao and his willingness to provide support in defiance of social norms. However, Jin Guangshan has no intention of welcoming his son into the family fold. Despite Nie Mingjue's efforts, Meng Yao, now a soldier, faces rejection once more from his own father. Instead of being acknowledged, he toils on the Langya Front under an abusive commander who frequently bullies him and takes credit for his ideas.

The war in Langya escalates, and Jin Guangshan, realizing the dire situation, calls for Nie Mingjue's aid. However, when Nie Mingjue asks about Meng Yao, Jin Guangshan pretends not to know anything. Determined to find him, Nie Mingjue presumes he will discover Meng Yao in his familiar role of cleaning up the battlefield. To Nie Mingjue's shock, he discovers Meng Yao not in a subservient role but using the enemy fighting style and techniques to kill his own commander. Alarmed at Meng Yao's ability to switch from a frosty, ruthless expression to panicked and tearful one, Nie Mingjue confronts him, accusing him of manipulation from the very beginning – starting with the incident involving the gossiping subordinates.

Meng Yao pretends to agree with Nie Mingjue's insistence that he turn himself in to his father. Instead, he stabs himself. When the horrified Nie Mingjue attempts to provide spiritual energy, Meng Yao seals Nie Mingjue's meridians and escapes. This unexpected betrayal leaves Nie Mingjue in a state of shock and fury.

In the ongoing tumult of the Sunshot Campaign, Nie Mingjue begins receiving detailed maps and crucial information through anonymous letters. Despite the strategic advantages gained from the mysterious letters, Nie Mingjue and some of his men are captured. All of them are taken to the heart of Nightless City, face to face with Meng Yao, now serving as the right-hand man to Wen Ruohan, leader of the Wen clan and the murderer of Nie Mingjue's father.

Nie Mingjue, unable to restrain his disdain for Wen Ruohan, insults the powerful figure. In retaliation, Meng Yao kills Nie Mingjue's subordinates, utilizing Baxia, Nie Mingjue's own saber, to insult him further with the painful memory of his father's death. A furious confrontation takes place, culminating in Meng Yao's plea for a slow death for Nie Mingjue at the Inferno Palace. Seizing a moment of vulnerability, Meng Yao turns the tables on Wen Ruohan, killing him when his guard is down. Meng Yao then rescues Nie Mingjue and absconds from Nightless City with both him and Baxia. However, upon awakening, Nie Mingjue rejects Meng Yao's pleas, choosing to chase him into a forest with Baxia in hand. The scene is interrupted by the arrival of Lan Xichen, who reveals the shocking truth—Meng Yao was the mysterious letter-writer all along and he was actually a spy who had to do questionable stuff in order to gain Wen Ruohan's trust.

Despite lingering mistrust, Nie Mingjue finds himself accepting a sworn brotherhood with Meng Yao, now known as Lianfang-zun or Jin Guangyao after being recognized by the leader of the Jin clan of Lanling as his son, and Lan Xichen. His intent is clear—to steer Jin Guangyao onto a righteous path through discipline and guidance. The three of them are known as 3zun from that moment onward.

After Wei Wuxian frees the remaining members of the Wen Clan from the forced labor camp, Nie Mingjue finds himself among the numerous clan leaders and cultivators summoned to Golden Carp Tower for an emergency meeting. During the meeting, when Jin Guangshan suggests that Wei Wuxian had spoken ill of his shidi, Clan Leader Jiang Cheng, the atmosphere becomes charged with tension. However, Lan Wangji, ever steadfast, swiftly corrects the misinformation. In an attempt to support his father, Jin Guangyao leaps into the conversation, claiming a lack of clear memory regarding the alleged incident; an assertion that Nie Mingjue keenly observes as a falsehood. It is only after the formal meeting concludes that the 3zun engage in a more candid exchange. Nie Mingjue, not one to let deception pass unnoticed, subtly hints to Jin Guangyao that his clever talk and hard work were observed, implying a level of scrutiny that goes beyond the surface.

In the aftermath of the fall of the Yiling Patriarch, Lan Xichen endeavors to repair the strained relationship between Jin Guangyao and Nie Mingjue. The remedy involves teaching Jin Guangyao the Song of Clarity, a musical technique aimed at countering the growing power of Nie Mingjue's saber spirit. Initially, Lan Xichen takes on the role of playing the Song of Clarity for Nie Mingjue. However, due to his commitments in rebuilding the Cloud Recesses, Jin Guangyao eventually assumes the responsibility.

Despite the initial steps toward improved relations, an incident disrupts the fragile bond between Nie Mingjue and Jin Guangyao. The Discussion Conference at Golden Carp Tower, Xiao Xingchen presents solid evidence that Xue Yang, a guest disciple of the Jin Clan of Lanling, was responsible for the massacre of the Chang Clan of Yueyang. While every other clan agrees to execute Xue Yang, Jin Guangshan refuses. Nie Mingjue, impassioned by a sense of justice, storms into the conference and directs a vehement lecture towards Jin Guangshan. With Baxia pressed against Xue Yang's throat, Nie Mingjue threatens to execute him on the spot. When Jin Guangyao attempts to mediate, Nie Mingjue sternly orders him to stay out of it. Jin Guangshan agrees to execute Xue Yang but later reneges on his promise, commuting Xue Yang's sentence to life imprisonment. This decision infuriates Nie Mingjue, who confronts Jin Guangyao at the pinnacle of Golden Carp Tower, demanding that he fulfill the promise to execute Xue Yang. The confrontation between Nie Mingjue and Jin Guangyao escalates into a clash of ideologies. Jin Guangyao, driven by fear of losing his position in the Lanling Jin Clan, argues for the preservation of Xue Yang's abilities in Demonic Cultivation. Nie Mingjue, fueled by his sense of justice, condemns Jin Guangyao's prioritization of political gain over righteousness. The argument becomes more and more heated until Nie Mingjue pushes Jin Guangyao down the stairs of the Golden Carp Tower as he calls him "son of a prostitute." Nie Mingjue attempts to strike a fatal blow with Baxia, declaring Jin Guangyao "beyond redemption." Lan Xichen, witnessing the escalating violence, intervenes to prevent further harm. The confrontation underscores the irreparable fracture in the relationship between Nie Mingjue and Jin Guangyao, with their conflicting ideals and moral convictions pushing them to the brink of irreconcilable differences.

Jin Guangyao, seeking to regain Nie Mingjue's trust, promises to bring Xue Yang's head within two months. Simultaneously, Jin Guangyao, with hidden motives, plays a dangerous tune. He accesses the Gusu Lan Clan's forbidden books, merging a section from the Collection of Turmoil with the Song of Clarity, creating a slow poison that catalyzes Nie Mingjue's impending qi deviation. As Jin Guangyao continues to play the guqin to soothe Nie Mingjue's saber spirit, he actually accelerates Nie Mingjue's descent into a qi deviation. The catastrophic culmination occurs during a martial arts conference held by the Nie Clan of Qinghe. In the throes of his deviation, Nie Mingjue mistakenly perceives everyone as Jin Guangyao, leading to tragic consequences as he inadvertently kills several people.

After Nie Mingjue's death, Jin Guangyao, recognizing the unusually strong resentful energy towards himself within Nie Mingjue's fierce corpse, dismembers the body and scatters the pieces to conceal his crime. Nie Huaisang, realizing his brother's body is missing, embarks on an elaborate plot to expose Jin Guangyao and retrieve Nie Mingjue's remains. After Wei Wuxian, revived in the body of Mo Xuanu, and Lan Wangji find Nie Mingjue's legs sewn to a different corpse in the ancestral hall of the Nie Clan of Qinghe, Jin Guangyao notices that someone is trying to find the pieces of Nie Mingjue's corpse, and sends someone to retrieve the torso, that is in the graveyard of the Chang Clan of Yueyang, and the right arm, that is in Yi City. However, the person he sends fails in his task. As they already suspected Jin Guangao being behind this, some time later, at a banquet in the Golden Carp Tower, Wei Wuxian sends a paperman after Jin Guangyao and discovers that he is in possession of Nie Mingjue's head. Jin Guangyao, adept at weaving intricate schemes, places the severed head alongside the remains of his own mother. However, Nie Huaisang finds it, and releases his brother's corpse, now complete, to hunt Jin Guangyao. After a tough battle, Wei Wuxian and Lan Wangji lock Nie Mingjue in a coffin, giving a pause to the chaos. At the same time, Jin Guangyao is caught, facing the consequences of his wrongdoings.

However, Nie Huaisang, driven by revenge, tricks Lan Xichen into mortally hurting Jin Guangyao. Wounded and desperate, Jin Guangyao breaks the coffin's seal using his blood and releases Nie Mingjue. In a last-ditch effort to save Lan Xichen, Jin Guangyao sacrifices himself, pushing Lan Xichen away. Jin Guangyao's neck is snapped by Nie Mingjue. The two sworn brothers end up sealed together in the coffin.

This coffin is placed in a cemetery watched over by several clans. The area within five hundred feet remains barren.

Fanon
One of the reasons Nie Mingjue and Jin Guangyao are shipped is because they both meet a tragic ending at each other's hands, when once there was fondness and trust between them. Some give them a happier ending in canon divergence stories. Others are also attracted to the angst surrounding their relationship. There are 1500+ works on AO3 tagged as NieYao. NieYao is the second most popular ship for both Nie Mingjue and Jin Guangyao.