Basically the Ur-Didact is an artificial intelligence now like the rest of his Prometheans. Also, if u look up the stuff from Toy Fair 2015, there is a Mega Bloks set called the Phaeton Gunship. It comes with a minifigure that is confirmed to be a Promethean. Weather he's a new enemy class, a living forerunner, or something else is pure speculation at best. But, I'm getting a feeling that this set might be based on an actual vehicle and character that will appear in Halo 5.