Zhang Tie had just returned to Xuanyuan Fortress for less than one day.
2 months ago, when the No. 1 corps of Fire-Dragon Corps arrived at the east bank of Weishui River, Zhang Tie had left Xuanyuan Fortress and deepened into the areas occupied by demons alone so as to seek for chances to promote to a shadow knight.
As the demon army gradually approached Xuanyuan Fortress, fights between human knights and demon knights increased on an increasingly larger scale. Therefore, it became more and more difficult for Zhang Tie to capture demon knights or refine water elements from them alone.
In the past 2 months, Zhang Tie almost met a team of over 100 demon knights in the areas occupied by demons. Generally, he had no chance to launch an attack at all. In such a case, he could barely make any achievement. With his powerful secret methods and Castle of Black Iron, Zhang Tie only caught 2 earth demon knights and 6 black iron demon knights.