Atheon was a robot tying all of the confluxes together, but we beat him with help from Kabr. He was an independent mind not supported by the bulk of the Vex. Crota was a weakling among the Hive gods, the youngest of the large Pantheon Skolas was just a Baron gone half-mad with loss and driven to extreme measures to keep his House alive. The Ahamkara bones in his back helped Oryx is more powerful than anything we've seen before. And he's pissed