Zaraki was orphan as a child.... maybe he's related to Bach? His Soul did overwrite someone elses sword...
It is quite interesting to note that while Zaraki had chipped his own sword, for Ichigo it was the other way around and the partial Bankai that he achieve and used in his first Bankai fight, had crushed him instead... now that Ichigo has finally obtained his true swords, his Bankai might be so demanding, so tasking, that he might be lying on the floor after 5 minutes of using it... then again, as the Zero Squad stated, he has grown up and become stronger at heart, spirit, body, mind and power...
I wonder what names will the Monk give to Ichigo's new swords in shikai and in Bankai. Probably both will have "Zangetsu" in the name, but there will probably be more to it. Black and White Moon Cutter ? Howling and Shooting Moon ? Well the "moon" should be in the name, but will it still be simply a cutting moon ? If one could be considered as the "Heavenly Chains", does this mean that the other one will be "Hellish Ropes" ?
Then again, it would be pretty awesome if one remained as the "Cutting Moon", while the other one had become a "Piercing Sun" and then Ichigo would put the moon before the sun while invoking his Bankai, thus creating the "Infinity Eclipse Slayer", or something like that ;p. Not to mention that there can be two type of eclipse, one is a solar one (nisshoku) while the other one is a moon one (gesshoku).
About Juha Bach, I could entertain that he may be a distant relative of the Soul King, this would explain why Qunicies call him "Your Majesty", why he has these unusual powers, and also why former Captain Commander Shigekuni Yamamoto Genrusai opted to seal him 1000 yrs ago instead of killing him, perhaps it was from respect for the Royal Blood.
However, I think it is a distant leap to link Zaraki to Juha Bach.
So far, many of the "Magic Hunters" have pretty hax power, way more hax than those of Fullbringers or even sometimes even those of Shinigami. It never was explained how they come to posses them, beside saying that they are simply humans born with special/powerful spiritual energy.
Basing on Bach's power and the power of the current Quincy, we can probably assume that many of the Magic Hunter Clans were either eaten by Bach, or assimilated/mixed with the Quincy. Among the already known characters, most likely the ones that are "Magic Hunters" while not being strictly associated with the Quincy (which are also one of the Magic Hunter Clans) are:
- Bach (well he started a Magic Hunter Clan - the Quincy, so he obviously is a MH),
- Orihime (damn, I so would like to see Orihime finally going berserk/loose and reject Bach so many times, that he would finally revert to his original form where he couldn't move, talk, or see, feel, or hear...),
- Royd & Loyd (their powers are also pretty hax, since technically speaking they would have been able to copy things even from the SK).
In over 1000 years, there wasn't anyone more worthy of the Kenpachi title than Unohana, besides Zaraki. At least one should exist, by being born and brought up in certain way, right :p ? Really, if one cannot make someone like Yamamoto sweat by simply swinging his/her sword, then that person certainly isn't worthy of the tittle of the Strongest Shinigami (Ichigo doesn't count since he is a hybrid, neither do the RG since they seem to be modified by the key-thing ?).
Going back to Ichigo's swords, Red Moon and Blue Sun/Moon can also fit (you know the Hollow part being white with red aura, and the Quincy having that blue flame that burns everything). I'm also wondering what color his Bankai will take, seeing as he has black swords in his Shikai already ? Probably white ;p.