User blog:Walker 454/Mysteries of Bleach

I've been a fan of Bleach ever since I found the manga and have read through the entire series in a short amount of time. Out of the many issues that have been raised about backstory one has always stuck out more to me than any other. And that matter is the cloak Ichigo was wearing after completing his bankai training using Urahara's techniques.

Does anybody have an idea what purpose the cloak filled, what its significance was or where it came from?