Damon is the main antagonist of White—Victini and Zekrom & Black—Victini and Reshiram.
He is a descendant of the People of the Vale and wishes to restore his people's kingdom to its former glory. To this end, he has gathered allies among other modern-day People of the Vale and is in pursuit of Victini, hoping to use it to reactivate the Sword of the Vale, the ancient castle at the center of Eindoak Town.
Depending upon the version of the film being viewed, aspects about Damon change. In Victini and Zekrom, he owns a Reuniclus, while in Victini and Reshiram, he has a Gothitelle.
(Source: Bulbapedia)