Undead Mage from a Cell

Gu Xi discovers a small problem. He has been clubbed and thrown into a cell. To avoid becoming the first player to fail before even completing the class change, Gu Xi decides to advance to the Undead Mage ASAP. “Big brother, did you call me out?” “I am Gu Xi, hoping to make a contract with you and borrow your power to become an Undead Mage.”