so in warhammer 40k you have the space marines. Their official name is the adeptus astartes. a group of 10 space marines are powerful enough to turn the tide of a war. The process of transforming a mortal human into a space marine is immensely painful and lethal, with a very low survival rate. the process takes 20 specialised organs and implants them into the body over the course of two years. these 20 organs are collectively called the geneseed. however the term geneseed is usually applied to only one of them, the progenoid. this organ is implanted in the shoulder/neck and contains the genes necessary to create the rest. other organs include the black carapace, which is implanted under the skin of the whole body and sticks out in places. it is used to interface with the space marine armour, as well as other technologies. then theres the bechers gland and lymans ear, implanted into the face and neck. these two work together to provide extremely advanced senses, hearing sounds no human could hear, and smelling with greater accuracy then the most purebred bloodhound. they can also see in lightless condition, spit acid and breathe underwater. there are also enhancements to the blood, making it impossible for a space marine to bleed to death, as well as brain modifications ensuring that a space marine cannot sleep, only hibernate/torpor. the geneseed isnt perfect however. many space marines suffer from... mutations depending on the origin of their geneseed.

so in warhammer 40k you have the space marines. Their official name is the adeptus astartes. a group of 10 space marines are powerful enough to turn the tide of a war. The process of transforming a mortal human into a space marine is immensely painful and lethal, with a very low survival rate. the process takes 20 specialised organs and implants them into the body over the course of two years. these 20 organs are collectively called the geneseed. however the term geneseed is usually applied to only one of them, the progenoid. this organ is implanted in the shoulder/neck and contains the genes necessary to create the rest. other organs include the black carapace, which is implanted under the skin of the whole body and sticks out in places. it is used to interface with the space marine armour, as well as other technologies. then theres the bechers gland and lymans ear, implanted into the face and neck. these two work together to provide extremely advanced senses, hearing sounds no human could hear, and smelling with greater accuracy then the most purebred bloodhound. they can also see in lightless condition, spit acid and breathe underwater. there are also enhancements to the blood, making it impossible for a space marine to bleed to death, as well as brain modifications ensuring that a space marine cannot sleep, only hibernate/torpor. the geneseed isnt perfect however. many space marines suffer from... mutations depending on the origin of their geneseed.