After Xue Fanxin's cultivation level reached the Martial Monarch Realm, she still had boundless power in her body. She could completely advance to the Deity Realm.
However, just as she was about to advance to the Deity Realm, the God's Seal appeared again and sealed all the power in her body that had not been completely absorbed and refined, causing her cultivation level to be stuck at the Martial Monarch Realm.
All of this was clearly the doing of the Star Abyss Emperor. He had temporarily removed and restored the God's Seal in Xue Fanxin's body, making her cultivation level only stop at the Martial Monarch Realm.
After Xue Fanxin advanced to the Martial Monarch Realm, she realized that the power in her body was still very boundless. She thought that she could steadily advance to the Deity Realm, but in the end, the God's Seal appeared again and sealed all the remaining power in her body, not letting her advance to the Deity Realm.