It would hurt a lot but not as it would if he had rejected his role.
Angelo had accepted the bond with the werewolves, which mean that his transformation would restore the broken mind links and the regular lives of the packs, but that wouldn't mean that they would be able to bond with their mates.
The only way the wolves would be whole was when the alpha king and queen had accepted their bond. But as they all knew, their queen was already on her way out of their world and was possibly thinking she was on her way to death.
Everyone looked forward to the first run with their rulers, but they were aware that their alpha queen was not with them. Most people were not happy with Rhian's choice and would wake up to hell the following day.
They all knew that because Rhian would have the worst transformation. That was because she was alone, had rejected the werewolf bond, and had refused to be what she was slowly becoming. She literally had no idea who she was in the werewolf world.
