The Black Snake's cocoon in Levi's heart was dormant.
A terrifying aura came from within the black cocoon, causing the Giant Rhinoceros, Man-Faced Spider, Siren, and Blood Whales Life Seeds outside to worship it.
It was as if something terrifying was brewing in the black cocoon, suppressing others.
Levi sat still, waiting for the day when the Black Snake broke out of its cocoon.
He had already stored a month's worth of food in the whale sac, enough to complete the transformation without eating or drinking.
If the transformation were short, it would take one day; if it were long, it would take seven days. If the transformation were not completed after seven days, the transformation would fail.
The process also requires a lot of energy. Many knights did not accumulate enough energy before going through the transformation. As a result, they failed at the last step. Some of them even became Lunatic Knights.