Zhang Yu is not afraid of the evil god becoming bigger, because the nature of the evil god determines that he can only be an evil god, and he will not completely fall into the chaos, otherwise he will become a chaotic creature.
Of course, the Great Chaos never rejects anyone who comes, and it can swallow whatever Taoism you uphold. Even the interaction between the Great Chaos and Yuankong all the time can be regarded as a process of engulfing but not completely engulfing, and it has also caused many changes.