As announced earlier this year, NCSoft has rolled out account migration for players of Aion and Lineage II, beginning today. The move will bring both games under one account, consolidating how the player handles their login, NCoin, and security. As mentioned in the release:
NC Accounts allow players to manage their Aion and L2 game accounts with a single email, which you will be able to change for added security–no more static account name! NC Accounts also share a wallet for NCoin, meaning that any NCoin you purchase can be used between your Aion and L2 accounts!
The migration is currently voluntary, but only temporarily. Following a grace period, users will be required to migrate their Aion and Lineage II accounts to NCsoft accounts in order to log in at all. Any unapplied items will not transfer over, so NCSoft recommends you apply them before making the move.
A small update, but an important one nonetheless.
(Source: NCSoft press release)