Confusion clouded Lex's mind as he repeatedly went over the information provided by his cultivation technique. The Regal affinity was supposed to make spirit energy extremely resilient, meaning its affinity would not be easily overridden and induced stability in whatever it affects. This was supposed to be the bedrock of Lex's breakthrough when he entered the Nascent realm.
This was due to the fact that, normally, when humans cultivate, Nascent is the realm in which their soul finally becomes strong enough and gains the ability to exist without the body. The realm was more complicated than just that, and included many things beyond the simple strengthening of the soul, but in context to Lex, it was a huge issue. After all, another ability of Nascent was to separate the soul from the body according to need, but Lex technically did not have an independent soul anymore.
