Episode 12 of Solo Leveling resumes right where Episode 11 left off, with Sung engrossed in a fierce battle against a relentless onslaught of knights. As Sung valiantly fends off the knights, he acknowledges that his reserves of combat techniques are dwindling. Despite this, Sung pours every ounce of his energy into the fray. Gradually, as Sung's strength ebbs, haunting whispers assail his ears, reminding him of detractors who have branded him a weak hunter and advised him to quit before it's too late.
Elsewhere, Chairman Go delivers a few solemn remarks regarding the third Jeju Island raid, clarifying his absence during Woo's moment of need. In stark contrast, Woo reveals that he attended the raid, fulfilling his security duties. Go acknowledges the colossal loss of life during that tragic event and understands that the survivors still bear the scars of that harrowing experience. However, he emphasizes that all hunters must learn to transcend their pain and brace themselves for the impending calamities.
Sung engages in a introspective dialogue with his past self. While the past Sung admires the physical prowess of the present Sung, he detects an undercurrent of weakness. As the knights continue to inflict damage, the past Sung harshly declares that the present Sung will forever remain an E-Rank Hunter, destined for mediocrity. Amidst the overwhelming pressure, Sung ponders if his past self's assessment is accurate, if nothing has truly changed.
Suddenly, the Player Log materializes before Sung, reminding him of his unfinished daily quest. Unable to fulfill it, the Player Log system transports Sung to the penalty zone. Upon arrival, Sung reflects on his plight, summoning healing potions from his store to mend the wounds incurred during the perilous job-change quest dungeon.
As Sung consumes the potions, the Player Log system alerts him that severe injuries render his potions ineffective, unable to restore his health points (HP). Thus, Sung concludes that he must await natural healing or a level-up. Soon, a plague of centipede monsters descends upon him, each matching his rank on their title cards. With determination, Sung engages the centipedes in battle.
Meanwhile, Jinah's narrative unfolds as she notices Sung's absence, wondering if he'll make it to the impending guardian-teacher meeting on time.
Back in the penalty zone, Sung, resting atop a defeated centipede, has vanquished all foes, leveled up, and significantly recovered from his wounds. He accesses the Player Log system to organize his equipment.
Curiosity piqued, Sung decides to explore the system's store and discovers a "Knight Killer" weapon, which he promptly purchases. Grasping the blade, Sung crushes the Rune Stone he obtained after defeating Igris. Upon crushing the Rune Stone, the Player Log reappears, revealing that Sung has acquired the skill "Ruler's Hand" - a skill that requires no mana and enables him to manipulate objects without physical contact. Sung attempts to move the centipede's corpse but finds that he still lacks the strength to manipulate heavy objects.
Returning to the job-quest change dungeon, Sung observes that the room is now swarming with even more knights than before. Armed with his new gear and skill, he devises a plan to confront them.
Elsewhere, a messenger informs Guildmaster Choi and his allies that they will soon arrive in the airspace above Jeju Island. Choi confronts Cha Hae-In, noting her apparent concern.Hae-In dismissed her concerns as unrelated to the impending expedition but candidly admitted to not having taken part in the third raid. Nonetheless, she empathized deeply with Choi's sentiments regarding the matter. Just then, someone perceived multiple sources of magical energy emanating from the depths of the ocean and hastily informed Choi and the others of the development.
The narrative returns to Sung, now locked in battle with the knights. Despite the Knight Killer blade aiding him, Sung senses an oddity in the area. Scrutinizing his adversaries on the battlefield, he realizes that mages are summoning knights through magical portals. This discovery prompts Sung to shift his focus to the mages, seeking to neutralize their threat.
After Sung vanquished one of the mages, several knights crumbled to dust, leaving him undaunted in his quest to overcome the remaining mages and press onward through the chaotic enemy horde. As Sung dispatched another mage, the surviving mages coalesced, pooling their mystical energies to transform their lingering knights into a formidable golem. Despite their valiant efforts, Sung emerged victorious, overpowering both the mages and the golem they conjured.
The Player Log materialized, announcing Sung's completion of the job-change quest. Sung pondered the implications of what lay ahead when, abruptly, the Player Log began displaying sinister messages of death and murder attributed to Sung. It then revealed his new job class: Necromancer. Confusion clouded Sung's mind; he craved a profession more aligned with raw strength. The Player Log queried Sung's acceptance of the role, and though he hesitated to decline, it was emphasized as a hidden class, returning to a binary prompt of "yes or no."
Sung deliberated, recalling his fierce battles with the mages and knights, and contemplating whether his path had been predetermined. After careful contemplation, Sung reluctantly embraced his fate and accepted the necromancer class. Upon bestowing this title, the Player Log further granted Sung a second class, the prestigious "Shadow Monarch." Additionally, Sung discovered he had garnered numerous accolades, wondering if his quest had reached its conclusion.
From the fallen knights, shadowy figures emerged as the Player Log prompted Sung to enter a command word for his "Shadow Extraction" skill. Choosing "Arise," ghostly knight apparitions rose from the corpses. The Player Log imparted knowledge about "Shadow Extraction" and "Shadow Storage" skills – one enabled him to drain mana to spawn shadow soldiers, while the other allowed him to retain and summon these soldiers at will. Sung noted that the success of Shadow Extraction hinged on the target's strength and the elapsed time since their demise, and that he had also gained shadow mages, each possessing distinct levels.
Wandering over to Igris's fallen form, Sung realized he could extract his shadow too. Recognizing a limit to his storage capacity, he dismissed several knight shadows. His attempts to extract Igris's shadow initially failed, with the Player Log informing him of two more tries left. As Sung persisted, Chairman Go's musings on the hunter-reawakening process echoed in the background, while Sung sought to persuade Igris to switch sides.
Ultimately, Sung succeeded in extracting Igris's shadow. The Player Log prompted him to rename Igris, to which Sung granted his own name. Igris and the rest of the shadow army bowed in reverence to Sung, acknowledging their new allegiance.
Elsewhere, Choi and Hae-In observed a magical beast on Jeju Island from their ship, ending the season with Choi's ominous remark about the beasts undergoing some form of evolution.
