World Trigger Manga is a very popular japanese manga that is written by Daisuke Ashihara. Ashihara also illustrates this manga and has done so for the past 3 years. He got his inspiration from Doraemon, another manga that brings futuristic into an everyday setting to create an impressive story.
This immense manga is all about a gate that has opened to another dimension. From this new dimension large invincible creatures come through and threaten everything mankind holds dear to them. To tackle this problem Ashihara created a mysterious group of warriors that have managed to co-opt the intruders’ alien technology to use against them and get their world back.
The main characters, Yuma and Osamu used to be in the opposite roles. This was back before the story was full made and Ashihara was still in the creativity process. If things had stayed that way Yuma would be a Border Agent and Osamu would just be a human.
Ashihara realised that creating a concept of opposites would work really well, as it had done in various other mangas. From this Yuma became a powerful Neighbor and Osamu, a weak Border Agent.
The main characters in this manga are:
A very intelligent and trusted companion to Yuma. he has a defensive trigger, which does have low strength but the plus side is, that it has a high level of durability.
Yuma is unusually short for his kind. He’s a Neighbor which is an interdimensional extraterrestrial race of humans.
Chika is the main heroine of World Trigger. Even though she’s shy, she works as a Border Agent where her main role is a sniper.
As for Yuichi, he’s the most laidback of all the characters, but that doesn’t take away from him being one of the most intelligent and influential agents in Border.
You can read the ongoing manga at World Trigger Manga.