Driven by Eren's unwavering determination, his mortal vessel was subjected to a thorough breakdown.
The relentless pressure within him spared not even his heart, brain, or vital organs, inflicting damage on every level.
Yet, Eren understood that this destruction was vital, the crucible in which the foundation for his Master Rank would be laid. Just as a mythical phoenix rises from its own ashes, so too did Eren's transformation require this process of complete destruction and renewal.
With every ounce of effort expended to establish this firm foundation, Eren's next step was to transcend his mortal bounds. Engaging his Soul Sense, he separated his consciousness from his physical form, allowing his body to surrender to the inevitable breakthrough into the B-Rank.
Crack. Crack. Break.
As Eren released his grasp on control, the pressure upon his mana core became overwhelming, leading to its ultimate destruction.