The Frost Crystal of Absolute Heaven is the inherited treasure of the Mu Family. The Frost Crystal of Absolute Heaven has the appearance of a small icicle but upon being crushed it with release an energy that congeals into a very hard ice barrier that can persist up to six hours against a high-level Sovereign. In the past there where three Frost Crystals but two has been used up and it unknown if more can be made. Mu Family Patriarch Mu Feiyan had promised the crystal to Mu Yubai but since he refused to get married, Mu Feiyan gave it to his only grandson Yun Che.
Yun Chu used the crystal while trying to save Little Demon Empress but the ice barrier was easily destroyed by Duke Ming. This was because the item could protect against level nine Sovereigns but Duke Ming was at the 10th level of Sovereign Profound Realm.