Gantz

With the space program attempting to travel to Mars, 21st century scientists were tasked with warming up the planet so that humans could survive on its surface. They came up with an efficient and cost effective plan of sending cockroaches and mold to the surface so that the mold would absorb the sunlight and the insect corpses would serve as a food source for the mold. It is now the year 2577 and the first manned ship to Mars has landed on the planet and the six crew members are ready for their mission. But what they find are giant mutated humanoid cockroaches with incredible physical strength. The crew members are easily wiped out, but not before sending a transmission back to Earth. Now, humanity will send elite warriors to exterminate the mutated bugs and claim back Mars.

Ten Years ago, Genichiro Izayoi died trying to stop the sorcerer Rebi Ra, and as a result Shinjuku became a playground for demons. And now, the day approaches when Rebi Ra will complete his decade-long ritual to plunge the rest of the world into chaos! As Genichiro's son, it falls to Kyoya to venture into the heart of Shinjuku and put an end to the sorcerer his father couldn't beat. Can Kyoya exceed his father's legacy, or will the demons of Shinjuku create Hell on Earth?