NCsoft, which is making some server changes and merges prior to Aion's transition to free-to-play starting on April 11th. Players affected by this can take a look at a new official FAQ to clarify any and all questions about what's going down on March 28th.
The short version is that most individual character data will remain untouched, but players with conflicting names will be given a random string of letters and numbers and a free name-change ticket. Players who wind up with Asmodeans and Elyseans on the same server will also be given the option to change to an appropriate race or transfer the offending characters to another server to adhere to the one-faction-per-server rule. If you've got more detailed questions, of course, the FAQ has more detailed answers.