6.5 MSQ spoilers

As I said in a previous thread, the fact that the original Golbez was a shard of Azem is all but confirmed. Not only did we see through his eyes in 6.4, with the non-textbox type of subtitles, but also in 6.5 Durante was certain that we were Golbez during the Memoria section of the dungeon. If you do that dungeon with duty support, the team even emphasizes how "He seems certain that you [the warrior of light] are Golbez".

Knowing how that dungeon ends, Durante kills Golbez (Azem) and traps his soul in the crystal. So, the 13th's Azem is currently trapped in a Memoria crystal. Whether we'll ever rejoin with it, I don't know.