Granisle Inscription was an unenchanted stone tablet that was inscribed with the participants’ names through some unknown magic. At that time, it only contained the names of four Night Liches and three Elder Liches. There were few rules that the undead must follow through and rulebreakers would be ganged up on by the others if broken. Such was considered to be the looseness of their relationship in Corpus of the Abyss.
This stone seems to have been carved from stone and has multiple short writings of the undead's names on it.
The tablet itself is unenchanted but serves as a legal document binding the members of Corpus of Abyss.