10 Video Game Characters You Didn't Realise MAJORLY Affected Sequels
1. Doug Rattmann - Portal 2
The elusive "Ratman" has always been a huge mystery in the Portal games. He is the only other survivor of GLaDOS' activation, along with Chell, but the only evidence the player can find of his existence are his temporary camps left throughout the lab complex.
This all changed when Valve released a comic titled "Portal 2: Lab Rat", shedding some light on who Ratman truly is and showing just how important his character is to the story of the sequel.
Finally appearing with his actual name, Doug Rattmann is shown to be a scientist who became increasingly more paranoid after GLaDOS killed all of the people in Aperture Science. He's managed to stay off her radar by sticking to the back walls of the facility, but he kept observing what was happening with Chell, as he believed she was the only one who could defeat GLaDOS and earn her freedom.
When Chell goes to hibernate at the end of the first game, it turns out the power in the facility is shutting down, and she will eventually die in the Cryo-Chamber. Doug saves her by putting her Cryo-Chamber into the Reverse Grid, effectively setting off the events of Portal 2.