User blog comment:Xilinoc/Everything but the Rain op. 4: Dark of the Bleeding Moon/@comment-5198194-20130328001941/@comment-4822693-20130328212325

I think that it's most likely that he does have a fire type zanpakuto. It would fit in with what we know about the Shiba clan, since Kaien had a water type. I think the issue of having getsuga tensho and being a fire type is very important. It means that getsuga tensho is a true technique and not a zanpakuto power, which explains why both Ichigo and Isshin can use it. Otherwise it would mean that they have near identical zanpakutos, and as far as we know that is impossible.