Kaita

A Kaita is a fusion of three beings into one single being.

Toa Kaita
A Toa Kaita is a fusion of three Toa. Once the beings fuse, they turn into a completely different Toa with another personality, mask, and weapons.

A Hordika can't form one since they lack the mental focus to stay together.

The first ones formed were Akamai and Wairuha, the Toa Mata Kaita.

Matoran Kaita
A Matoran Kaita is formed when three Matoran fuse. As long as they have seperate elements, they can be formed.

None have appeared in the storyline.

Turaga Kaita
A Turaga Kaita is a fused form of any Turaga of different elements. Unlike the other Kaita, a Turaga Kaita required four Turaga to form.

None have appeared in the storyline.

Rahkshi Kaita
The Rahkshi Kaita were fusions of three different Rahkshi. Only two have appeared so far:
 * Kaita Za
 * Kaita Vo

Bohrok Kaita
A Bohrok Kaita was a combination of three Bohrok into one. Unlike most Bohrok, these had two Krana.

None have appeared, but two are known to eixist: It is possible that Kal forms of these two existed as well.
 * Kaita Ja
 * Kaita Za

Bohrok Va Kaita
The Bohrok-Va Kaita are fusions of three Bohrok-Va into one larger being.

None have appeared in the story, but two were combiner sets.