HHH and Vince blame each other for Reigns walking out of Mania with the title. This results in McMahon reminding HHH that Vince is still the boss. Stephanie gets between the two while they get ready to fight... she ends up slapping Vince. Vince then fires both HHH and Stephanie.
Vince comes out the next week and selects someone else to run things on Raw... someone who is neutral, someone who does not have an agenda, someone who will make sound decisions... the Heartbreak Kid, Shawn Michaels.
Michaels starts as a fan friendly authority figure who makes the right decisions and makes good calls... but eventually, things get out of control and he convinces Vince that he and HHH can co-manage. They end up not getting along and in conflict with each other- this leads to an eventual feud over control.