Board Thread:Questions and Answers/@comment-6019258-20130325050319/@comment-893506-20130401012250

SenNoKuroiHonoo wrote: Yes, maybe he acquired a gigai that's same to Isshin's and Urahara's so he gradually lost his Shinigami powers and learned to focus on his Fullbring powers. Remember he took Ichigo's Fullbring and combined it on his own? That's when the bankai thing started as Ichigo's Fullbring contains traces of his Shinigami power.

Kugo was a Human, and as a Substitute Shinigami, he was not a true Shinigami either. A Gigai is acquired by Shinigami for them to inhabit. It doesn't make sense for Kugo to have a Gigai, much less inhabit it. Like Xil said, because Kubo never elaborated on Kugo's past, we don't know what happened with him and his powers in the past.