My Mouth Is Connected to Giant Beasts from Another World, I Became the Strongest by Drinking Water

"Look carefully, this guy died just after smoking a cigarette on the rooftop..." Qi Dong was this unlucky guy. He just went up to the rooftop to touch fish for a while during working hours, and then he was stabbed in the stomach by a lunatic who came out of nowhere. He originally thought he would die like this, but when he was about to die, he was saved by a box with a mouth. Before Qi Dong could be happy after escaping from death, he was told by the box that he only had seven days left to live. The only way to survive was to absorb enough souls. And the method of capturing souls is surprisingly simple, just drink water with your mouth? But... He looked at the alien giant beast at his feet that had been beaten into a puddle of flesh by him, and then at the heart of the giant beast that had been drained of blood in his hand. Qi Dong smashed the ten mouths on his body at the same time, and asked the box in confusion: "Great Immortal, are you sure this is water? Why do I get thirstier the more I drink?"