Why did Abby kill Joel in The Last Of Us 2?

Yes, it might come as a shock, but The Last Of Us' Joel won't be seen in later parts of the game. Abby, under immense rage, kills Joel brutally with a hockey stick. Before you start mourning the loss of such an essential character, we will explain to you why and how it all happened. At first, many people who are wondering who killed Joel and who is Abby' She is a strong character belonging to The Last Of Us game series and one of the few remaining people who is finding a cure to what has affected all mankind in the game.

In the game, we get a glimpse of Joel sharing his emotions to one of his friends about how he saved Ellie from doctors who were trying to do a surgery that would have killed her in the process. He shared that he had to kill all the doctors and soldiers in the process of saving the 'FireFly' i.e. Ellie from dying. This is important because it marks the moment where it shows how much Joel cares about Ellie whom he has been saving for a long time.