I could give you my ideas about enviroments and races liying inside those "Wasted Tunnels" under Bara Magna:
ENVIROMENTS
THE LABORATORY:
The place where GB worked on many species, like Toa, Glatorian, Matoran. all the enviroment is fully with earth, it haves so much flora that gave birth to imnumerable possibilities of livin fauna there.
there are Capsules, machinary, pieces over the land, some Capsules have death experiments inside, and some in stasis as well.
there are tunnels that bring you to a big hall covered with metal, and is abundant of capsules, prototype weapons, bodies and machinary that was to live inside Mata Nui robot
THE CHEST:
the Darkest and hottest area of all the tunnels ever meet.
There are entire lakes that end in waterfalls, and there is a gigantesc red Nucleus that expires a surprising heat, there are "Temples" placed on constructions ribcages in the edges of the walls.
The Flora is terribly abundant because of the water waterfalls and the nucleus that gives them heat, all are in formations of Jungles and Swamps.
INHABITANTS:
THE LABORATORY:
There are Beast that call themselves "Verahk" living there, they are adapted to the place where they live, they are organic, and ugly, and they got some kind of Stalactite Metals spikes over their backs. they can control elements after such mutations given by the GB experiments.
Also there are other creatures that make be call "Setoran" (Settler matoran), they are Completely Metalic, some of them lack parts in their bodies, which they have replaced with weapons and harmful machinery for the life, in spite of being Mechanicals, they need food, for which they fight with the Verahk for obtaining food, some are of great size, but the majority they are small.
Their category is based on " Prototype Matoran "
Senrah and Zeirus:
They 2 are brothers, the two are considered to be " Welcomers of the apocalypse " by Their incredible skill of fight and mental experience, they have mechanical creatures that expire fire for his feet, are similar to a Horse, and it is necessary to have elegant when these are alone because these creatures since they can turn very violent sigh aggressive.
Senrah controls Fire
and Zeirus controls thunder
both uses Spear Launchers as shoot weapons after they discovered them in the Laboratory Hall
THE CHEST:
No one Knows what lurks there, but it's know that in the Jungles there are Ape-like creatures, they are massise and are freaking Violent as Strong.
in the Swamps there live aquatic creatures that will make you wish never birth if you found them in the dark.
there's not very information of what live in the Nucleus area or the Waterfalls area.
By a Skrall, there's info that in the Temples over the Ribcages constructions there inhabit Glatorian like people that have Replaced some members for metallic versions of them, they are bigger than a common Glatorian but not less dangerous than a Skrall, Their kind bases on something similar to Ciberpunks.
The Females of the tribes are bigger than the men and they specialize themselves in the control of firearms.
The males have a rough Serpent-Like skin that allows them to resist the heat of the Nucleus to withdraw energy, Machinery and weapon of this place
There are more places in the Tunnels that still inexplorated and there's no idea of What lives There.
PICTURES COMING SOON PEEPLE!