What is a kakuja?


Okay this is several questions. For one, what exactly is a Kakuja? I mean, I
get that they're extra kagune obtained by cannibalism, but what causes that to
happen? How come Kaneki's takes the form of a centipede? All I know is it's
somehow related to Yamori, but how did Yamori trigger this change in Kaneki?
And why did it cause Rize and Yamori to become one with him?




> A kakuja (赫者, red one, kakuja) is a kind of ghoul with a transformed kagune
> that clads the ghoul's body. Though it is rare, it can occur through
> repeated cannibalization. When a ward has a higher ghoul to human ratio,
> cannibalization is more common due to turf wars and limited food supply.
>
> Sometimes, the transformation is incomplete, and such individuals are called
> half-kakujas (半赫者, han kakuja).

[Source](http://tokyoghoul.wikia.com/wiki/Kakuja)

Kagune for kakuja's tend to be more specialized. For example,
[Arata](http://tokyoghoul.wikia.com/wiki/Arata_Kirishima)'s kagune was the
Armor. It just happened to be that Kaneki's kagune when in his kakuja state
take the shape of a centipede.

This could also be associated with Kaneki's mastery at manipulating kagune. In
Tokyo Ghoul;Re a member of the Quinx squad named [Saiko
Yonebayashi](http://tokyoghoul.wikia.com/wiki/Saiko_Yonebayashi) has extreme
control over her kagune. Because of this, she is able to freely change the
shape and size of her kagune, ranging from
[nets](https://vignette.wikia.nocookie.net/tokyoghoul/images/6/6e/Saiko_forms_net_with_her_kagune_and_captures_Urie.png/revision/latest?cb=20170222150532)
to [huge
fists](https://vignette.wikia.nocookie.net/tokyoghoul/images/5/53/Saiko_forms_massive_fists_with_her_kagune.png/revision/latest?cb=20170222151501).

