He did not bring Chu Zhong Tian with him, considering that his realm was too low.
Chu Zhong Tian had told Lu Chen everything that happened outside the Haotian Secret Realm.
Even Nascent Soul Stage cultivators might die at the hands of the ancient beasts, not to mention ordinary Golden Core Cultivators.
Even Danyang Zi, who did not confront the ancient beasts head-on, ended up burning his lifespan and met with death in the end. One can imagine how much stronger these ancient beasts became after leaving the Haotian Secret Realm.
But Lu Chen did not charge into Ten Thousand Demon Mountain blindly; he had his own considerations.
Danyang Zi died because, to some extent, he had nowhere to go and was literally worn out to death.
And if he went to Ten Thousand Demon Mountain, he would be relatively more flexible. Even if he couldn't defeat them, he could still escape.
