JAZZ: Juggernauts Against Zealous Zealots Chapter 0 (One-Shot)

The group known as "JAZZ" (Juggernauts Against Zealous Zealots) is at the head of a rebellious coup, aimed at protecting their home from a mysterious invasion of else worldly beings and the government tasked to "quell this invasion". Brought together by the portal scientist, Dr. Benjamin Morgan, JAZZ is well-equipped to handle anything heading their way!

Strange portals have been appearing over the city of Neo Haven for months and no one has a clue as to why or where they come from. They house destructive monsters and humanoids from other dimensions, usually hostile creatures, and the city's only task is to stop their rampage with weapons they've procured from research from past incursions. This is seen as a valiant effort from the government to protect their people coupled with their new city shield defense system. Still, the rebel group established from past incursion battles figures out that their stories don't add up and they begin to start their own investigations.

Where are these portals coming from? Who could be manipulating them? Why just over the city of Neo Haven and how long have these really been happening?