What is the Spirit Card's Power?
 

For LWW, we currently delve into Blade as Kenzaki and Friends battle the Undead. And one Rider, Chalice, wields the Spirit Human card.

Now SPOILERS AHEAD, the Human Undead card is never scanned like other Rouze Cards. It's only scanned on Chalice's belt and he uses it to de-henshin (among other spoilerific things).

It has never had it's power officially stated, so while we watch the Two of Hearts be an important plot point in Blade, let's theorize it's unique power.

I think it's shape-shifting.

Technically, he's not even untransforming. It's explained that scanning a card through the Chalice Rouzer, rather than giving a specific power, actually mimics the undead associated with the card. He's not de-transforming, he's changing his own appearance to match that of the Spirit Human.

As for Spirit's effect, I really don't have much idea, but I don't think shape shifting is it...

Oh yeah, forgot about that... Power of Heart?

It's possible. He's much less prone to violent outbursts when in his human form...

That and the Human Undead isn't as primal and vicious as the others.

uhh....spiritual powers? like psychic powers or something

Rapid firing arrows from the Chalice arrow? I guess that would be its power since all other category 2s are enhancements for a Rider's weapon attacks

I always got the feeling that, since it's SPIRIT, it would have some kind of astral projection type of thing. Like a spying motif. Kind of.

Cheesy as it may sound, but humanity. If you watch episode 46 Human Undead says that Joker does not want to return to being a raging beast, also probably the reason why he willingly let himself be sealed.