User blog comment:Xilinoc/Ch. 670 - The Perfect Crimson/@comment-1351982-20160414114434

Weird and disturbing thought, maybe Hitsugaya's powers prior to this were like the theory of Cryonics, or suspended animation, except he was still mobile. His spiritual pressure "froze" him, hence why he didn't "age." So he's thawing??? Otherwise good on Kubo for keeping his promise that Hitsugaya would complete his Bankai (and making is slightly less creepy for his fangirls 😉).