Well, I have been thinking a lot that there is a high possibility that Ichigo is somehow related to the Soul king(king of the soul society) and as the anime shows the main hero as a powerful person there is a possibility that Ichigo might be the Soul King Himself.
And if he is the soul king then, Ishinn(Ichigo's Dad) carries the captain cape and I think I saw at a filler episode that it was written zero on his back, so that definitely means that Isshin is the captain of the zero squad which means that instead of being the soul king(As he is Ichigo's Dad) he is the protector of the soul king so, Now comes the real question, "does that mean that Isshin isn't Ichigo's Dad and he is just his protector who might of Brought Ichigo in the real world to protect him or something like that.
In case u r wondering in which episode Isshin's number was shown, then it was shown in 304 i think the one in which ichigo, ishida all were shown as frankestein, vampire and other ghosts. And when isshin comes to hunt the ghost it is clearly shown.
And if he is the soul king then, Ishinn(Ichigo's Dad) carries the captain cape and I think I saw at a filler episode that it was written zero on his back, so that definitely means that Isshin is the captain of the zero squad which means that instead of being the soul king(As he is Ichigo's Dad) he is the protector of the soul king so, Now comes the real question, "does that mean that Isshin isn't Ichigo's Dad and he is just his protector who might of Brought Ichigo in the real world to protect him or something like that.
In case u r wondering in which episode Isshin's number was shown, then it was shown in 304 i think the one in which ichigo, ishida all were shown as frankestein, vampire and other ghosts. And when isshin comes to hunt the ghost it is clearly shown.