9. Julius Little - Saints Row (2006)
There are so many damn betrayals in the Saints Row franchise that you're better off just distrusting every NPC at this point, as was perhaps best evidenced by the first game's explosive ending.
The protagonist, commonly referred to as "Playa," is invited onto Alderman Richard Hughes' private yacht in the game's closing cutscene, before a bomb suddenly goes off and the end credits abruptly roll.
Though many suspected that Playa's pal Julius Little - who also happens to be the Saints' leader - was responsible, this wasn't actually confirmed until Saints Row 2.
In the sequel, it's revealed that Julius blew up the yacht because he didn't like the direction the Saints were going in, and knew that Playa wouldn't simply stand down.
Saints Row 2 opens with Playa having spent five years in a coma following the yacht explosion, and the game thankfully grants players the opportunity to mete out some bloody revenge against Julius, capping him in the head at the end of a side mission.