The Scum Is Adaptive 

Yu Sheng didn't look surprised. "It would be easy for your group to deal with them." He said. It isn't because he underestimates the strength of the demonic cultivators, nor overestimates their group's abilities, but because he trusts their group's capabilities. 

Qian Lin and Jing Hei have undergone the trials of the Intersect Competition, and they have soaked in the Spring of Life, having its blessing thus their strength increased to Nascent Soul Stage cultivators. Lei Qing's strength is also shying away from the Nascent Soul Stage after she experienced a breakthrough during the Intersect Competition. Lei Ling and You Rou may not have experienced their breakthrough during the Intersect Competition, but they did after the war against the demonic cultivators broke out. 

There's also no need to mention Qian Tian. Although Qian Tian is the youngest elder in their Qianxu Sect, his strength is nearing his father's, Qian Shan's, strength.