Illusion.

As for killing Archimonde and the Heart of Darkness—the heart and man in the center of Toussaint—it does not benefit Yoriichi nor incur any loss to him. Unlike letting go of Radovid, which requires him to humble himself and be beaten in terms of ego, and which might eventually yield a physical benefit, these two slightly powerful mortals provide no gain at all. 

Although their elimination has no direct effect on him, in the broader context of the entire multiverse civilization, they serve as a good motivator to drive every sentient being towards a great sense of unity to address the crisis.

As Logain Albar said, when there is no external enemy to confront, everyone starts looking within themselves, leading to unnecessary conflicts—much like the nonsensical disputes prevalent in modern society in Richard's past world.

Comparing this modern age to the 19th century, when groundbreaking discoveries such as quantum mechanics, general relativity, electromagnetism, germ theory, and the discovery of electrons emerged one after another. The modern age is filled with complacent and content people who do not benefit society as a whole, severely lacking compared to the era filled with conflict.

Because of this, it is better to let Archimonde and the Heart of Darkness live until a certain threshold. History has already suggested that civilizations as a whole become more sophisticated when driven by era-specific conflicts and a subconscious desire to escape the clutches of war.

One example of this is how scientists, in response to the threat of world war one and two, have been driven to solve problems and address global threats, reflecting a collective response to external pressures and aggressions.

"Still, I need to be careful. Remember, Yoriichi. You want to create a controlled disorder that produces something new. Not a disorder that plunges the world into meaningless destruction."

Sighing, since becoming Lord of Chaos seems really hard, Yoriichi shook his head and focused on the current conflict, which is the aftermath of the Conjunction. Knowing that he does not want to deprive himself of the inspiration for discoveries that could lead to a eureka moment, he decided to continue his life as a Sun Breathing Herald.

However, before doing so, he needs to cull individuals or races that are reaching the threshold of moral degeneracy, specifically those like Radovid, who target children and those who cannot defend themselves. Because of this, Yoriichi plans to kill Radovid later, immediately after obtaining the benefits from the psychological manipulation model created by Margarita and others.

"Alright, let's do this."

After calculating all possible outcomes and considering the risks of being taken advantage of while shutting himself off from the physical world, Yoriichi instructs all the microtubules inside his body to halt his entire wave function and sense of consciousness.

Like a robot, his body then flies all over the world and across the three realms, killing anyone who has reached the threshold of moral degeneracy or anyone with a destructive mindset that does not benefit the multiversal civilization as a whole. After roughly twenty years later, he suddenly awakens to find that two of the Mythic Path holders are already able to move their eyes and try to look at him.

Turning his head toward Loki and Melitele, Yoriichi then sends electromagnetic waves directly into their acoustic sensory systems in their brains, saying, "Don't worry, it will be over soon. I just want to do some cleaning."

Turning around and wanting to continue the culling, Yoriichi is stunned by a new discovery within his body. He observes that his Kryptonian physiology has evolved to the next stage—Cosmic Armor Superman—simply due to his age. Not only has he reached the highest level ever achieved in the Kryptonian DC comics, but he also senses that there is another layer of breakthrough he needs to achieve in order to reach the next evolutionary level.

With quantum computation providing a subjective simulation, Yoriichi examines the Planck Scale and cannot help but sigh in disappointment as he sees that his conjecture is correct. The moment mortals approach the limit of linear progression, the cap on their progression expands to accommodate the fragile physical world, which cannot hold the concept of infinity.

The Planck temperature, which just a moment ago had a value of 10^32 kelvin, now grows larger and larger to 10^64, making his Breathing Technique completely invalid because he cannot progress further with the new constants of physics that differ from his scientific knowledge.

This means that if someone reaches the maximum level of 20 in D&D, the GM will create a new set of levels to accommodate the player, so they can continue to have fun and enjoy the adventure. And in this case, the fractal world of this universe, connected to infinity, provides a new Planck Scale for him to discover and be inspired by.

This process then will continue on and on endlessly until even the highest glorified mortal in the four multiverses is no more than an ant in the grand scheme of things, reducing them to mere high-level individuals who are just the first few players on the board of reality.

Sighing, he mutters, "Fucking depressing."

Seeing the illusion of linear progression that strives to reach infinity but can never attain it, since anything that can be measured must be finite and reachable, Yoriichi performs a quantum computation. This instantly causes his Superman Physiology and Sun Breathing to evolve further, as he still has one inspiration left from the Xianxia world.

However, he also knows that this inspiration will eventually reach the limit of his future self, recognizing that he lacks the knowledge to accommodate the ever-expanding physics of the physical world. Letting out a resigned breath, he acknowledges that he doesn't want to become a singularity and reach true infinity by forsaking his free will for the good of the world and becoming just a mathematical equation.

Deciding that he still wants to be selfish and enjoy the world, Yoriichi creates a model of his advancement to the highest limit his mind can conceive. Drawing inspiration from a wide range of sources—literature, fantasy, mythology, physics, biology, physiology, language, and anything else that has exhausted his mind—Yoriichi develops a progression model for his Physiology and Breathing with 65,535 levels, inspired by the level cap from Fallout 4.

With quantum subjective calculations firing inside all of his Kryptonian microtubules, Yoriichi finally smiles, realizing that he has completed the culling by the time he reached about 50,000 levels or so. As general relativity becomes increasingly distorted due to the energy equivalent, he observes that Loki and Melitele can no longer move their atoms, seemingly frozen in time. Knowing that this is also an illusion of being stopped in time and cannot reach absolute zero, Yoriichi shakes his head, lets out a resigned breath, and continues his duty.

"Alright, Yoriichi, let's fucking do this."