Natural fusions are a very interesting, but underutilized concept in the story of Bionicle. To bring them back to the notice of community, here is a little rundown of numbers in regards to the possible Kaita:
-the usual team of 6 Toa (for example Toa Mata) can form 20 possible different Toa Kaita.
-the First Toa Team which consisted of 8 Toa, could make 56 possible Kaita.
-Toa Mangai who had 11 Toa, could potentially create 165 Kaita combinations, but because of the element redundancy, they only had 70 at their disposal.
-there are 364 possible elemental Toa Kaita combinations; 455 if Light is included and 560 if both Light and Shadow are included.
-and finally as there are 42 different Rahkshi, they have potential to make 11480 different Kaita. Seeing as Rahkshi Kaita unlock a unique ability every time they form this fusion, this means 11478 new abilities we have never seen before!
(Now waiting for the mocs for all those Kaita)