For most martial artists and demon gods, traveling through the outer realm of the starry sky requires taking an ark.
Firstly, because dangers lurk in the outer starry sky, there are perilous zones that even ancient emperors would find dangerous upon entry.
There are also dangers like void turbulences.
Moreover, using an ark consumes much less spiritual power compared to traversing with one's own body in the endless starry sky.
However, for Chu Fengmian, traversing the Tai Luo Stellar Domain, he always directly uses his tunneling light. He doesn't rely on external forces, after all, the spiritual power consumed in short-term flight isn't much, and Chu Fengmian can sustain it through divine vein recovery.
But traversing with the body is only feasible for short durations. In the long term, even with divine veins, he cannot fully recover.
The Canghai Stellar Domain is dozens of stellar domains away from the Tai Luo Stellar Domain; crossing it by oneself is extremely difficult.
