Update: Zenimax Online Studios have returned to clarify further, stating that their original information was incorrect. ESO will only use the disk for verification, and won't require a key at all.

Original article below:

Zenimax Online Studios have confirmed via the official Elder Scrolls Online forums that disk-based copies of Elder Scrolls Online for Xbox One and PS4 contain a single-use-only serial key that will be required for play.

Elder Scrolls Online will mark a first for Xbox One, requiring users register online using the bundled key before being able to play. Disk-based copies of the game can still be used for installation purposes even when sold, but a new player will have to purchase a serial key separately to play.

Elder Scrolls Online is Zenimax's attempt to take a bit of World of Warcraft's MMO pie, based on the near-unanimously popular Elder Scrolls RPG series. The game had a troubled start on the back of mixed reviews. ESO peaked at around 1 million players before announcing it would devolve into a subscriptionless model, with a version they've jarringly dubbed "Tamriel Unlimited".

A spokesperson from Zenimax Online Studios clarified speculation over serial keys on their official forum:

Hey there folks. To clarify, you will need a unique game registration code in order to play the game, and used copies will not be eligible to receive a key if the code has already been redeemed. It works the same way as the PC version in that the code included in the box is to activate your ESOTU account and the discs are for installation purposes. If you own the disc but don't have a key, you'll be able to install the game and reach the login screen, but you won't be able to log in and access the game without an active ESOTU account.

Despite ESO's side step away from subscriptions, Zenimax Online Studios will want to ensure that the cost of entry and in-game micro-transactions will be enough to fund the game's servers and support staff, akin to MMOs like Guild Wars II. If you were planning on purchasing the game and then then selling if you don't like it, just be aware that the re-sale value probably won't be that great.

The console market remains largely untapped for the MMO genre. The only MMO available for Xbox One - Neverwinter Online - has recently announced an active player base of 1.6 million, making it the number one free to play title currently available for the console. So there's certainly a market!

Have you played Elder Scrolls Online? What's your take on the game? Hit the comments.

Elder Scrolls Online launches for both Xbox One and PS4 on June 9th, 2015.