As account merging, Never heard of such a thing in any game. Besides graal Like Jarace said ( if he is referring to how you can make a house and buy items and get stuff before identifying an account and getting it added to the account).
I don't think they will ever merge accounts or ever allow such, Since it would probably be buggy as absolute hell in about every way I could imagine it to be. The only thing I can think they will ever do that is in any regards similar is one day actually add a feature to change a accounts email address. Since it is a pretty modern thing in almost every game (Can't even think of a game besides graal that doesn't allow that even) and it just adds more security, And allows players to continue using their account even when they can't access their emails anymore.