Curse of the beast lord/Princes of hell.
This ring was also found in the Challenge Tower. Cyrus, a very impatient wizard/warlock, was trying to identify all of the magic items that were found. After not being able to figure out what the ring did safely, he put it on. The ring bonded with his flesh and a gem appeared on the back of his right hand with what appear to be gold vines going up his arm. Inside the ring a malevolent presence made itself known to Cyrus, trying to make deals. When the group was in mortal peril, Cyrus begged the thing to take over to save his friends. It did. Cyrus’s body transformed into what can only be described as a balrog and was only restrained due to the elder vampire that was in the room with everyone else. Upon him allowing it control over his body, however, Cyrus unwittingly allowed it to bond with his soul, making their existences intertwined.