No characters should be lost in the merge, but it’s important to note that your characters will be limited by your total number of character slots available. Your total number of slots on Fey Forest will be equal to your highest number of slots from the three prior servers, but “overflow” characters will be inaccessible until you delete some of your characters to make some room. Assuming your roster wasn’t full on all three servers, however, you should be able to log in and start playing today; here’s hoping to a minimum of issues for affected players and characters alike.
Source: Official Site