User blog comment:Wolf night10/The Final Getsuga Tenshou/@comment-1591878-20100621025751/@comment-3274506-20101215162836

Let's get something straight here, Urahara never taught Ichigo GT. He taught Ichigo how to listen to his Zanpakutou. Zangetsu taught him GT, as it is an ability of Zangetsu. As you have mentioned other Zanpakutou have similar abilities, such as Benehime has Scream, but it is not the same as GT.

That being said, the real question here is how does Isshin know GT? Can the souls of Zanpakutou have children also? Ichigo is obviously a child of a Shinigami and a Human, the first of his kind as far as we know. So is Zangetsu a child of Isshin's Zanpakuto? This is the first time out of 300+ episodes any Shinigami has had the same ability as another Shinigami.

As far as the Final Getsuga Tenshou goes, Look at Byakuya, he has 3 ways to use his Bankai. First release form in bankai is all the sword pieces from the hundreds of swords. 2nd form is he can slow down everything within the sword circle he uses with hundreds of swords around him. And the 3rd form we have only seen once when he defends his families honor against "The strongest Shinigami" from the guy who betrayed his family. He uses a special attack that kind of takes on a form of an eagle like shape starting at the tip of his blade.

Also, look at Ichigo's hollow mask, it has changed designs everytime he defeated an Espada. Most recently when he killed Ulloqoro (Spelling). This seems to point to the idea that he consumes hollows just like hollows do to get more powerful. They will have to explain that more, as Ichigo has already said his mask feels heavier when he first uses it after defeating Ulloqoro.

Speaking of Ulloqoro, he is the only Espada to have a 2nd release...kinda makes you think Ichigo might have something above Bankai.