Yuan–Arc

Yuan Guang and Arc’s mentor–disciple relationship is founded not on trust alone but on a binding exchange: Arc will teach him cultivation, and Yuan will dedicate himself to opposing Manhattan and the Nuclear Path. The Unspeakable Vow makes that bargain consequential beyond the conversation in which they strike it, while their later lessons test what Yuan is prepared to learn—and what responsibilities come with his growing power.

The Bargain and Its Stakes

Arc agrees to train Yuan only on the condition that he form an Unspeakable Vow with her. She requires him to destroy Manhattan, any students he may have taken, and his plans, whatever they are. Yuan initially objects that he is nowhere near strong enough to carry out such a task. Arc answers that she will set no deadline: he may need years or decades to reach Manhattan’s level, but he must keep working toward the goal. If Yuan passes up a reasonable opportunity to destroy Manhattan or abandons the objective, the oath will destroy his core.

The proposal turns instruction into a commitment to a future conflict. Yuan’s immediate weakness does not persuade Arc to make the terms easier; instead, the absence of a deadline allows the impossible demand to stretch across his life, while the penalty prevents him from simply withdrawing. The relationship therefore begins with a sharp imbalance: Arc controls access to the knowledge Yuan wants, and the vow attaches a potentially fatal cost to the purpose she sets for that knowledge.

An Oath Made by Both Sides

Yuan accepts after considering the offer, then puts his hand on his bullet-core as Arc directs. Before she speaks the oath, Arc warns him that he can still abandon the Path of the Gun. Yuan’s resolve holds. Arc vows on her core to teach him everything she knows and make him her disciple, provided he never becomes a friend to Nuclear Path cultivators, defeats Manhattan and his followers, opposes their plans whenever possible, and ultimately destroys Manhattan—even if it takes centuries.

Yuan repeats the terms in his own version. He promises not to befriend a Nuclear Path cultivator and to defeat Manhattan and his followers once he has the power to do so; he also commits to opposing their plans whenever possible or reasonable and destroying Manhattan in time. His phrasing preserves the core demand but makes room for his present limitations and for what he judges possible or reasonable. The vow is mutual, yet not identical in wording: Arc sets an absolute long-term direction, while Yuan states how he can undertake it.

After Yuan speaks, he feels an invisible grip close around his bullet-core. A force from the Dao takes heed of the words and fashions them into a chain, leaving faint pressure on his soul as a continuing reminder. The promise is not merely a private understanding between teacher and student; it becomes a binding condition that Yuan cannot abandon. Arc acknowledges his determination—or foolishness—and confirms that, since a vow is a vow, she will teach him everything she knows.

Instruction with Limits

The instruction Arc offers is practical as well as ambitious. She says she can teach Yuan to make his own bullets, giving him a way to address his ammunition shortage and shoulder responsibility himself. Her help does not mean she will fulfill his broader objectives for him: she insists that he must carry those out alone. The arrangement gives him a means to become stronger without transferring his revenge or its consequences to his teacher.

Their lessons also depart from the rote training Yuan has encountered elsewhere. He reflects that the sect instruction he had seen consisted of drills, spars, and lessons built around following orders and climbing ranks. Arc’s approach appeals to him more. When she returns the Saint Heckler and Kalash Angel after deciding he can handle himself, she tells him to discover their capabilities in the field. Her teaching thus includes handing responsibility back to Yuan: he must learn what his weapons can do through use, rather than wait for every answer to be supplied in advance.

Arc also refuses to let training become detached from its effects. When Yuan mentions cargo he plans to deliver back to Fleshmarket, she points out that the bullets he has made will kill innocent people too. Her warning places the cost of his newly acquired ability beside its usefulness. Yuan wants both sides to lose, but Arc’s challenge makes clear that the ammunition he creates does not distinguish between his enemies and those caught in the conflict.

Advancement as a Condition of Apprenticeship

Arc sets a firm threshold for further teaching. When Yuan leaves, she tells him to return with a qi pill or not at all: the lessons so far have only brought him up to speed, and he must cross the Third Coil before she will teach him the real material. The condition gives their relationship a continuing structure. Arc has accepted him as a disciple, but access to deeper instruction depends on demonstrated advancement rather than the vow alone.

Their exchange about Yuan’s soul reinforces that cultivation is not simply a climb along a single track. Yuan tells Arc that he has seen his soul’s shape as Bullet Hell and that a Moonlight cultivator identified it as the Path his soul wished to take. Arc answers that Paths exist within Paths: the Gun branches into many roads, and Bullet Hell is only one of them. She does not treat Yuan’s revelation as the end of his development or as a replacement for the training she has set before him. Instead, mentor and student remain joined by a dual commitment: Yuan must become strong enough to pursue the oath’s demands, while Arc undertakes to teach him a discipline whose possibilities exceed the first shape he has seen.