GATE: Thus the United States of Canada Fought There!

(A/N: Everyone thank Wattpad Sokal7 for helping me bring back this story. It took a very long time, but I've managed to bring it back. I made some changes but almost all of it is the same.)
==========
Summary: What if during the 'War for Independence', instead of just 13 colonies choosing to secede from the British Empire, it was ALL the colonies of British North America that chose to fight for their independence. After winning their independence, the colonies would band together and unite to form the United States of Canada. Throughout its history, the USC has fought for its own existence in multiple wars and their actions have changed the course of human history. Despite all the faults and setbacks, the nation was forced to endure, the USC stands as one of the major superpowers in the world. However, everything changes when a GATE like structure appears and out came a roman like army. After eliminating the invaders and going to a world of fantasy, the USC soon encounter another GATE structure and are shocked to learn that it leads to a Parallel Earth, one with a radically different history. After encountering the JSDF, the people of the parallel Earth are soon in for a shock when they meet their alternate counterparts, especially the Parallel Americans. The course of human history for both the Alternate and Parallel Earth's will change forever, one that could either lead to peace... or total war.
==========
Pairing: OC x Harem