>>259731688>>259731362>>259731916The head is absolutelyy required biologically.
Nerve signals are quite slow and require large amounts of processing so they need to be placed as close to the brain as possible, and thus a full four out of our five senses are on the head.
In addition, the head moves independently of the body allowing for image stabilization, a wider field of view, being bale to look behind yourself, angling ears to track sounds, allowing the nose and tongue to inspect objects closely, etc...
The skull is also BY FAR the most durable part of the body, the chest cavity has to MOVE and is thus very loose, flexible, and weak. It also needs massive amounts of cooling and thus cannot be central in the body.
Finally, the "all eggs in one basket" argument actually FAVORS the head structure, as in nature losing any of your major sensory organs is almost a death sentence, as is damage to your brain. By putting them all together in one place it not only has constant sensory coverage to prevent sneak attacks but can be defended by sacrificing the rest of the body to block damage.
Even In Killy's case, where he's made of superalloy or something, because of his regeneration it's actually even MORE advantageous to block shots with the body and go all out hardening the skull since theoretically he could probably regrow his entire body if his head survived an attack. Plus it may be that the reason his head is so strong is that it CAN'T be regenerated, being made of an advanced material impossible to replicate without external machinery.
And all that doesn't even matter because since Killy's mission is to find the NTG, he has to appear human or he'd never be able to gain their trust or cooperation, and almost everyone in the city has the ability to do at least superficial scanning, which would immediately detect if he had weird inhuman organs or if his head was just an inflatable decoy.