Why Do the Skeletons I Summon Get Stronger the More I Fight Them!

I quit my job, emptied my savings, and rented an abandoned cold storage—I was crazy in the eyes of my colleagues. The day the gray bird crashed into the city, I was the only one who knew it was not bird flu. The countdown of the black classic reached zero, the infected person broke open the iron door, and a skeleton crawled out of the pages. It slashed the corpse's neck with a knife, then turned and pointed seven meters below the ground. Shelves containing tons of supplies are lifting off the ground.