Swallowing fire-spirit medium. Shen Cong meant to eat a little of it and digest it, and by that direct route increase his Firestarter grains and complete the Firestarter-grain gradation of nerve-gold.

Firestarter-grain gradation was a theoretical change, and Shen Cong had no idea whether it was correct.

At any rate, after he had ground up and eaten a fist-sized piece of fire-spirit medium, the numbness in his body did not lessen in the slightest, and he felt nothing special that might have been Firestarter grains being absorbed.

Two hours later Shen Cong understood that digesting fire-spirit medium directly had failed.

Because he wanted to go to the lavatory.

Over this recent stretch he had eaten essentially no food at all, so he went to the lavatory only once a week. He had been only yesterday, and by the state of his body he should not have felt anything until the following week. But he felt it now, which certainly meant the fire-spirit medium had gone undigested and given him diarrhea.

A fist-sized piece of low-quality fire-spirit medium wasted.

"Digesting it directly isn't realistic. I can't swallow fire-spirit medium the way a jin beast does, and I'm afraid the reason is that I have no jin core. For jin people and jin beasts the jin core is their own carrier, which is why a jin beast can swallow fire-spirit medium directly."

"An iron person really is stronger than a jin person, but the iron core is separate from the body proper, two parts rather than one, and that has indirectly produced the awkward state my evolution is in now."

Once the inspiration was in hand, Shen Cong's thinking opened out rapidly, and he could push forward layer by layer and look at evolution from the height of the whole.

The evolution of nerve-gold was no longer a change in one isolated stage of tissue; it was bound up with the entire structure of metal life. Taking nerve-gold's abnormal condition as the reference, he gathered the whole process of evolution, from the beginning to now, onto a single thread.

From first to…