Lu Qing had been using his Dharma form to fight against the three-headed evil spirit.
At the beginning of the battle, he had considered summoning his Dragon Soul to assist in the battle. However, when he realized that he was fighting with his transcendence body, he was already certain that he could suppress his opponent. However, even if he summoned the Dragon Soul, he would not be able to kill the other party.
In that case, there was no need to summon the Dragon Soul. He might as well keep it and use it as a trump card. The effect would definitely be better.
As a trump card, Lu please's way of using his Dragon Soul was not just to be a combat helper.