Somewhere in Tokyo, there is a room. In that room is a black sphere. Periodically, people who should otherwise have died are transferred to the room. There, the sphere gives them special suits and weapons, and sends them out on a mission to kill aliens here on Earth. While these missions take place, the rest of the world is largely oblivious to them. These missions are lethal - few participants survive them. The sphere calls the shots, and it is not the slightest bit nice. Its name... Gantz.
Sci-fi
The misadventures of Son Goku, Krillin, and other friends from the original story, by Ooishi Naho
Vampires have been defeated by Humans. A story about them wearing collars. Wait - you're mistaken, it's not like that!
Suddenly, a fleet of ships with mysterious superweapons called the “Fleet of Fog” appeared all around the world. Humanity didnt have the technology to fight such a fleet, so they were driven out of the sea.
Seventeen years after the battle, Gunzou Chihaya and his crew mates aboard the I-401 and the personification (Mental Model) of the I-401, Iona, started fighting the Fleet of Fog.