Multi-verse Fusion-works

[Title is a placeholder.]
In the year 20XX, most of history was wiped out during an event known as the 'Versal-collision'. Which was a time when portals to different universes opened around the world and released beings who tried to kill or enslave the earth. As a result, 'the above world' was mostly destroyed, humanity went underground, and re-created civilization. The government created 'fusion' as a way to combat the creatures, but it's been abandoned as a government practice.

People still use fusion however, case in point, Dr Blake Fudo Stein, one of our main characters. He uses fusion to contain his boredom, combat loneliness, and hopes to create a group strong enough to overpower the government, so he can become the emperor of the surviving world.