Looking back I remember reading somewhere (Spadows blog?) that Nexon had told that there would be only 2 "Legends". Other 3 are successors of the old Legends. After 3 released Legends you were able to safely say that the 2 legends who survived were Aran and Mercedes.
So then you would have to think that Phantom is the successor of the original thief legend, right? In that case his storyline doesn't fit it.
Not only is it weird that he used to be a famous thief, meaning he would have to be quite old, he also knew the previous empress and in the maple anime Althena and Mercedes act like "omgosh Phantom is back". So he must've been then fighting against the black mage? Then how did a mere human survive all those years if he wasn't frozen up like Aran?
If he's a successor...Then who's the original thief hero? I haven't seen an npc, what so ever.