Donyell crossed into Gambit’s life when he entered into a relationship with Bella Donne Boudreaux, who had been divorced from Gambit for a while by that point.
However, it was soon revealed that Donyell was manipulating Bella for his own purposes, and when Gambit came back to New Orleans and reveals what Donyell has been doing, they split up.
Donyell is primarily affiliated with the New Warriors, and he inherited his current identity, Night Thrasher, from his brother, Dwayne.
Presumably Donyell would serve in a similar romantic rival capacity for Gambit, and if he is indeed showing up in the movie, this would be his first appearance outside of the printed page.