The Isshin extravaganza (Slight Spoilers)

[Batman2o4]

I dunno if this has already been done, I didnt really search in-depth.
Though we all know that Isshin is quite possibly the most awesome character in Bleach, there are lots of things we dont know about him.
When Urahara was training Ichigo for the S.S. Saga, he said that he originally had shinigami powers, which had just been awakened by Rukia's donated ones.
That brings us to the conclusion that he's inheriting these powers from someone, and I dont think it's aunt Betty.
The suspicion that Isshin was more than just goat-face was increased in the more recent episodes and fairly old chapters, when he appeared, decked out in shinigami gear.
Now, not only do we know that Isshin passed on the power to be a shinigami to his son, but he also passed down a lot of it (Considering how easily he took down the low-class espada Aizen sent to earth).
Though we cant blame Isshin for all of Ichigo's insane amounts of reiatsu, we can blame him for some of it.
Not only his power displayed that he was powerful (..duh.) but so did the ripped Captains cloak draped over his shoulder.
Which raises the question, who is this man?
I'll post my findings in a little while, after I've heard a little bit of what you guys have to say.

[Ranryou Roga]

Yes i do believe that Isshin is a captain that could have changed his appearance when he came to earth. That way maybe Rukia or some of the others didnt know him. He has great spirit control. Due to the fact that he was able to find it form everyone intel he used his power to kill grand fisher. He is a captain level Soul reaper.

[Hitsugaya389]

Originally Posted by Batman2o4

When Urahara was training Ichigo for the S.S. Saga, he said that he originally had shinigami powers, which had just been awakened by Rukia's donated ones.
That brings us to the conclusion that he's inheriting these powers from someone, and I dont think it's aunt Betty.

Yes that's true that Rukia's powers awakened His. But, if you go further in the series, you will find that Ichigo looks exactly like Kaien Shiba. I assume that Ichigo is Kaien's reincarnation and he got some of his powers from him.

AND

If Ichigo's sisters are Isshin's daughters, then why aren't they also able to turn into Shinigami???

[Ranryou Roga]

Maybe because they are only beginning to unleash the power within.

[Hitsugaya389]

But what if they aren't Isshin's and they are just adopted???

[Ranryou Roga]

I think the Noble Shiba family and the Kurosaki family are connected in some way.

[Batman2o4]

Well Karin and Yuzu's powers weren't awakened as suddenly as Ichigo's were (ie. Shinigami powers being thrust upon him). But because of Ichigo's subconscious leaking of reiatsu will slowly awaken and sharpen their powers. As it's doing to his friends at school, (Already displayed by Chad and Inoue and is beginning to display Tatsuki's (Seeing Ichigo in spirit form, seeing his Shinigami badge when it's supposedly invisible to humans, etc.))
Rukia really caused a chain reaction; Ichigo's powers awakened, so is everyone around hims'.

As far as Shiba-Kurosaki relations, it was brought up at my other forums, but I think it's unlikely.
It's true Ichigo does certainly resemble Kaien but I think it's just fluke.
Their personalities are too different for him to be his reincarnation, too.
But then again, Kaien might have gone through the sassy-teenager stage while growing up.

[Hitsugaya389]

not true. Their personalities are almost exactly the same.Even thier speech is similar. That leads me to think that Ichigo is Kaien's reincarnation.