Any critique for my fantasy world? Be as harsh as you want the more brutal the better.
So I have this huge crater 9km deep which is the central area of the world and story which is actually a huge ancient creature buried under thousands of years of rocks, dirt and greenery though at the very bottom is its mouth type thing. It also secretes a toxin which changed the evolutionary path of the creatures in the crater making them more viscous and overall more terrifying getting worse the further down.
There is a town which was built around it during the ice age as due to the emense size it kept the area warmer around it due to its body heat leading to civilization being established there. The civilization built a huge wall around the outside of it protecting it against the Iva age and the frost with gates leading to the outside four in number.
Though the creature began to get hungry so released an airborne toxin or part of itself which infected all human hosts and made them wander into the crater to be consumed due to being connected with the hive mind, though some humans had a genetic resistance which left them to re populate humanity.
This toxin was still dormant in there dna being seen in future generations where some children around 1/1000 where born as a sack without any organs or vital humanity requirements instead having a link to the creature with kept them alive telepathically after a few months developing into a human fetus. These kids where thrown in the crater due to people not knowing what to do with them though later they established camps where they would be raised then sent into the crater to be fed to the creature so it would stay dormant and not attack the civilizations, the kids had no idea about the creature whatsoever being mislead as they entered.
Once the kids enter the crater there link with the creature becomes far stronger making them more powerful but also making it more difficult for them to leave when they try to they become awfully malnourished and will later die as the telepathic nutrient and vital system has changed its operating distance to be shorter effectively trapping the kids in the pit making them travel ever closer.
The way the link works is a small particle of the creature is carried down from the parents generation to a few kids depending on the strength of the particle the kids become linked with the creature, though in cases where the link isn’t strong enough the child will be born as a normal fetus or will die from malnutrition and from the lack of vital human functions in the sack faze or a mix of both fetus and sack.
The kids have no idea about the crater being alive or the mysteries of it while only higher up government officials have knowledge of it so fear doesn’t grow through the civilization. Though a secret know to no one is the kids thrown down the pit “sack kids” built a make shift civilization down there though is very poor with numbers ranging from 1-100 depending on seasons and the danger of the area during the time.
Any suggestions of how I can add upon this world