During these few days, Erian had not only stabilised his Peak Double-Supercell Titan power, he also digested all of his battle experiences that he gained in the past few weeks. He used those experiences to increase his own battle effectiveness and efficiency.
Currently, Erian could have an even fight against the first Superman student, who had mastered two powerful martial arts without even using his 'Heart Refining'. Without a doubt, this was a huge step forward.
After all, Xietien was recognised by the martial world as a Demon-level Warrior, being able to evenly fight against him meant that Erian's power also reached the Demon-level. In other words, Erian had almost reached the peak grade among all the younger generation Warriors. If he included the 'Heart Refining', Young Master Malevolent Frost, Young Master Constatine and the 'Malevolent Frost Fast Blade' Atticus probably would be the only three, who were able to evenly fight against him.