The Highbreed are former villains in the Character What universe.
Character What: Ultimate Hero
The Highbreed Commander returns in The Return of the Highbreed, Unlike all the Highbreed who were reform after the genetic repair from Omnitrix used by Ben Tennyson, The Highbreed Commander hasn't change his ways from being evil after the genetic repair. The Highbreed came to Ponyville to find Ben Tennyson with Shadow Joe, Knowing that Ben Tennyson spend most of his time with Shadow Joe and his friends. The Highbreed Commander have a battle with Shadow Joe, Shadow Joe jump on the Highbreed's back and use his heat powers to dehydrate and weaken the Highbreed.
Character What: The Last Stand
In Villains Turn Evil, Some of the Highbreed were at Shadow Joe's Villain Museum with the other redeemed villains looking at the exhibits.