The risks are high yet the gains are small, and sometimes there are no gains at all. This is the fundamental reason why most deities are unwilling to enter dangerous situations. In truth, even though it is widely known that entering divine realm dangers may very likely yield no returns, every day there are still deities who venture into these perilous places.
However, not every deity is as fortunate as Zhou Tian. When entering divine realm dangers, back then nearly eight or nine out of ten deities lost their lives on their first attempt. Because so few managed to survive such dangerous situations, it eventually became widely accepted that once you entered, you were guaranteed not to leave alive.
