He can use an appearance modification station to give himself tattoos. The tattoos allow him to add symbol resistance to his very skin.

The aesthetic look of the protagonist is one who is heavily covered in exotic, vaguely militaristic equipment and clothing. The items are usually new when he adopts them, but experience accelerated wear due to his harsh lifestyle. Sometimes he needs to add repairs to an item, but his look is not that of a ragtag survivalist. With so few people left in the world, he has his pick of the remaining equipment. To this he then adds modifications. This includes functional modifications like adding more pockets, reinforcements, cargo loops, caribeeners, armor plates, etc. This also includes symbolic modifications such as gluing police badges and crucifixes to his armor, or engraving symbols in his sword, or electroplating gold or silver onto bullet tips.

Cargo pants, jungle boots, tank top, stylish jacket, backpack, holsters, canteens, first aid kits, gas mask, dust mask, balaclava,

Several pistols, assault rifle, machete-like short sword, fighting knife, k-bar, flash light, head lamp,

Clothes are generally charcoal colored. The look is influenced by asian cyberpunk clothes for males.

The protagonist won’t kill animals to eat their meat, nor will he imprison them for domestication. He will eat old canned meat he finds though.

The protagonist was a figure like Andrei Sakharov or Stanislaw Ulam - someone who was a key figure during the development of the nuclear weapons in that world. The protagonist has lost their memory of those years due to the the viral encephalitis resulting from the germ warfare agent.

(Interesting note: Ulam suffered life threatening encephalitis after his work on the atomic bomb.)

The protagonist uses modification stations (located in safe havens) to improve the effectiveness of his weapons and armor. He uses tattoo stations to add tattoos to his body.

mental illness interpretation:
The protagonist is probably seriously mentally ill, hallucinating that ghosts who died during the war are haunting the world and attacking him. One strong piece of evidence favoring this interpretation is that if he consumes anti-psychotic medications, the number of ghosts he sees is greatly reduced.

Despite not having a pre-war history of mental illness, he suffered a serious fever, during which he could easily have suffered some brain damage. He’s experienced numerous head injuries, which could result in brain lesions. Also, mental illness can just happen late in life.

sane interpretation:
The protagonist might not be mentally ill and the ghosts might be real. He has no history of mental illness before the war.