Origins of the Bahrag and Kal

[Lewa0111 Nuva]

Apologies if this has been answered before, but I wasn't able to find any information either way on the subject. Did Greg ever explain the origins of the Bahrag and Bohrok-Kal? I know Bohrok are transformed Av-Matoran, and that he confirmed Toa of Light cannot become normal Bohrok. Do Toa of Light become Bohrok-Kal and/or Bahrag, then? Were the Bahrag and Kal just created with the MU like most other beings? Are Kal regular Bohrok exposed to Protodermis (a sort of "Bohrok Nuva")?

 

Been thinking a lot about Bohrok weirdness lately and this issue started bugging me (No pun intended ).

 

Lewa0111 Nuva

[The 1st Shadow]

The Bahrag were created by the Great Beings. They are completely unique; not of any existing species or variations thereof.

 

The Kal were mutations of normal Bohrok, though what exactly caused this change is still a mystery to us. Some believe it may have been Energized Protodermis, but I think that idea was shot down. Personally, I like the idea that there was some unknown factor of uncertain power that we never saw. 

 

On that note, we have no idea where the krana came from. During Maze of Shadows, the Toa Metru found a carving that depicted the Bahrag putting something into a pool of something and raising up krana from it. This substance (or some variation of it) may be what caused the Kal transformation. But even then, we still don't know what it is.