Endless Night Apocalypse: I Have a Billion Tons of Life-Saving Supplies

[Apocalypse + stockpiling supplies + frenzied farming + decisive and unsentimental + building a faction] A supervolcano erupts, and a cloud of ash blankets the world. Those who breathe in the smog mutate into monsters. The long night settles in, and the apocalypse begins... Chen Yan awakens the Radiant Mark ability. His body can take the place of the sun, not only allowing plants to photosynthesize, but also compressing their growing cycles to the absolute minimum! While others chew on rotten meat, he grows vast fields of tender vegetables. While survivors kill each other over half a loaf of bread, he has already started large-scale animal farming. Two crates of bullets for ten sacks of potatoes, one cannon for two pigs. Fair prices, no haggling. A monster army at the gates? Carbon-based lifeforms are no match for modern weapons. Hostile factions covet what I have? First, ask my brothers if they’ll allow it! My name is Chen Yan. The long night is endless, but watch me grow a dawn!