One Million Stars Falling From the Sky - not so much revenge against a specific person or people, but a guy generally lashing out at society for his troubles... he later finds a specific target...
Sleeping Forest - stalkers, guys trying to get revenge, secrets, etc. No one is what they seem.
Both are similarly depressing stories...
And since Prosecutor Princess was mentioned... I thought Park Shi Hoo played a very similar role (though very different character) in The Princess' Man. The second half was definitely a revenge story.
