Su Xiao obtained a total of 8 true attribute points, one more than he predicted. Among the numerous prompts, what he cares about most is the 'Black Abyss Authority,' and he certainly knows what the Black Abyss is—it is a perilous place within the void.
Strangely enough, many major races within the void will send their young members into the Black Abyss 2 to 3 times. According to the Succubus Lilim, the 'thing' she received in the Black Abyss is unique.
Although Su Xiao already has access to the Black Abyss, this doesn't mean he can enter it immediately. He first needs to obtain an invitation or a World Key, or something related to the Black Abyss to enter it through Reincarnation Paradise.
