Overall, the anime of World Trigger sticks close to the manga, but there are tweaks. For example, some character expressions might be emphasized differently, and certain scenes might be shortened or expanded for timing. However, the core story remains intact.
The manga about problematic children from another world had not been completed yet. This manga was a fantasy manga created by the Japanese manga artist, Shokuyama. It was published in 2011 and has since been released in multiple series with different endings. Although the manga author has promised to constantly update and release new stories, the manga is not officially completed yet, so readers can still see different versions of the manga.