The Last of Us is not suitable for all ages. It has a complex and often brutal story. There are scenes of people being attacked by infected creatures in a very violent way. The language used can also be coarse at times. Given all these factors, it's mainly targeted at an older, more mature audience who can handle such content.
The 'Last of Us' origin story is mainly about the start of the post - apocalyptic world in the game. It shows how the Cordyceps fungus outbreak began and spread, which led to the collapse of society. It also details the early days of the main characters and how they got involved in this chaotic and dangerous world.
The Last of Us was not a comic originally. It was first developed as a video game, which gained significant popularity and later inspired other related media, but the comic came later.