Runic Disc

The Runic Disc is a key item used to record data for the Nyzul Isle Investigation Assault. Upon entering Nyzul Isle Investigation, whomever clicks on the Rune of Release to start the mission has the Runic Disc of record for the Assault. Upon successfully completing the Assault and exiting, any progress is saved to that person's Runic Disc. If the Assault completed is a multiple of 5 (or greater), the information saved to the Runic Disc will allow the holder of the Runic Disc to start the Assault mission at higher floor. (once you complete floor 5, you can start on floor 6; once you complete floor 10, you can start on floor 11, etc.) This does cost additional Nyzul Isle Tokens, however.

If you start from floor 96, and defeat the boss on floor 100, the person whose Runic Disc was used to start at floor 96 is granted a Runic Key and all data on their disc is erased. This means that their disc will no longer be usable to start at a higher floor, unless they progress their way through the Nyzul Isle Assault floors all over again. What the Runic Key does is largely unknown at this time.

It also should be noted that the person who gets the armband to start the Assault does not have to be the same person who uses their Runic Disc to pick a floor.