I am surprised that nobody mentioned this earlier... It's been in the back of my mind since the moment I came across this.
Now before you continue...
MAKE SURE YOU WANT SPOILERS ABOUT REVAN & HK-47!!!!
Good, now... For Revan.
During a level 30ish flashpoint, you go and rescue a Jedi Prisoner which turns out to be Revan. He was stuck in the prison after he was captured trying to kill the Sith Emperor in the Unknown Regions. You rescue him and he heads to the Imperial's Flashpoint to do some awesome stuff.
This is after the Republic's flashpoint. You meet HK-47 as the 2nd to last boss and absolutely destroy him. Then you move onto Revan and kill him also... Ya. You KILL Revan at lvl 30 with a few sh*tty low levels...