Secondly, Gu Yuena had the Dragon God Core with her after all. Even though she and Tang Wulin each represented a part of the Dragon God, she could not fuse herself completely with the Dragon God Core yet. However, the Dragon God Core's power was clearly present still. Moreover, it was within Gu Yuena's control. The Dragon God Core was not only effective in restoring her consumption but also in elevating her.
Hence, the beasts were under the assumption that Tang Wulin was no match for Gu Yuena. In a battle of one-on-one, Tang Wulin would not stand a chance of winning.
They realized that their assessment was perhaps inaccurate when they witnessed Tang Wulin mobilizing the life force of the Eternal Tree in the distance.