He hadn't actually ascended but simply created the illusion of ascension; even Zhi Ling and Fire Feather were kept in the dark.
If Zhi Ling and Fire Feather chose to follow him, he would naturally share the relevant information with them.
Zhi Ling and Fire Feather exchanged a glance and both said, "Master, we choose to stay in the Spirit Profound Realm to train and grow. We don't wish to be a burden to you but to become your assistant."
"Good, since you have made your decision, then train well. I look forward to your future transformation," Lin Yi nodded in approval, which was exactly what he hoped for. After all, once he left this time, it was uncertain how many years he would spend comprehending; he couldn't possibly have Zhi Ling and Fire Feather accompany him all the time.
After communicating with these Spirit Beasts, he returned to the Cave Mansion and informed Tai Xuan Dao Palace, as well as Big Monster City, about his upcoming ascension.