Liebe_

Cultivation Realms (Based on Reverend Insanity)
Cultivation in the Gu World is based on the fusion of primitive essence with Gu to increase the level of a Gu master.  In the case of the protagonist, his Celestial Diagram allows him to mix this system with Qi cultivation techniques.
Here is the progression of cultivation realms that we will follow for the protagonist:
Apprentice of Master Gu (1st to 9th level)
Initial phase where Master Gu collects and learns to manipulate weak Gu.
Han Feng has already passed this phase and advanced to the Master Gu Realm.
Master Gu (Rank 1 to 5)
Each rank advancement increases the capacity for primitive essence and control over Gu.
Han Feng is currently Rank 1, but secretly cultivating.
He needs to evolve without drawing attention, concealing his progress.
Master Gu Immortal (Rank 6 to 9)
Transcend mortality and refine the immortal essence.
Han Feng can mix the power of Qi cultivation, creating a unique method.
Sovereign Venerable (Rank 10 - Demigod)
Few reach this level.  Example: Venerable Immortal Renegade.
In the future, Han Feng may reach that level and challenge the supreme powers.
Supreme Being (Below only the Dao)
Transcendent existences that touch the Supreme Dao.
Only legendary figures have reached this level.

The Heir of the Celestial Diagram

Chapter 36: The Secret Method of the Underworld

Han Feng kept his breath steady, his eyes analyzing every detail of the underground chamber. The elders' conversation revealed more than he expected. There was something bigger at stake, and the Sect of the Dark Mist would spare no effort to complete this mysterious ritual.

But his attention was soon drawn to the inscriptions on the altar. Among the ancient symbols, he noticed a set of runes that emitted a faint glow. Approaching carefully, he touched the cold surface of the stone, feeling a wave of dark Qi spread.

Suddenly, his mind was flooded with a torrent of information. The altar contained an ancient cultivation method called Dark Chaos Refinement. It was a technique that absorbed energy from the underground and transformed it into pure Qi, accelerating the cultivator's advancement without causing external fluctuations.

Han Feng shuddered. This technique was perfect for him! He could increase his strength without drawing attention, remaining hidden while preparing for the future.

The technique required a sacrifice. To use it, he would need to absorb the essence of nearby living beings or use a powerful catalyst to balance the energy. Han Feng frowned. Killing to cultivate was not something he desired, but perhaps there was another way.

Without hesitation, Han Feng sat on the cold floor of the chamber. He channeled his Qi and began to follow the instructions recorded on the altar. The black energy began to envelop his body, infiltrating his meridians.

The process was painful. An overwhelming force pressed on his dantian, trying to corrode it. But Han Feng resisted, refining that energy and converting it into something of his own. His Qi grew with each breath, becoming denser and more refined.

When he opened his eyes, a deep glow passed through them. He felt his strength increasing. Although he was still at Rank 2, he felt that this method would soon take him to Rank 3. But now, he needed to get out of there before anyone noticed his presence.

With one last look at the altar, Han Feng activated the Celestial Veil Art and slipped through the shadows, escaping without leaving a trace.