Wish We Knew More About This Sword And Its Creation But Squad Zero Having A Countermeasure Against The Soul King’s Power Checks Out - Blog Posts

Ise Clan

I thought Shinken Hakkyōken was a cool reveal and I wished we got more backstory to it and I'm hoping we might get some in the anime and/or hell arc.

I always thought it was a failsafe in case the Soul King broke free. When the seals on him were removed his powers did attack the Sereitei and the Shinigami.

My guess is that it was specifically designed by Oetsu to combat the Soul King. Oetsu's bodyguards are examples of zanpakuto with built in powers.

It was revealed that the Ise Clan suffers from a curse that kills all men that marry into the family and also that they only birth daughters.

Nanao's mother speculated that it was Shinken Hakkyōken's doing.

It made me think about the incorrect relationships between Shinigami and zanpakuto that could develop which were mentioned by Oetsu.

I also thought of Oetsu having a harem of female zanpakuto spirits to serve him. I think maybe Shinken Hakkyōken has a similar mindset as his creator and sees the Ise Clan as his wives and him as their true husband.

Oetsu regulates male zanpakuto to working behind the scenes. But I think Shinken Hakkyōken is more extreme so kills off their husbands and ensures they only have daughters.