Because you like Lilo in Lilo & Stich
Kenzo Tenma would have never guessed that ten-year-old he saved would later become a deadly serial killer intent on "thanking" him. See them in Monster (TV Show).
Sylar's victims are found all over the country, many with their brains removed. See them in Heroes.
Lelouch vi Britannia is a high school student by day, masked destroyer of tyrannical empires by night. See them in Code Geass.
Manipulative, gorgeous, and sharp as a tack, Blair Waldorf is a classic product of the Upper East Side. See them in Gossip Girl.
Once a loving family man, James Heller is now dark, damaged, and hell-bent on getting revenge. See them in Prototype Series.
Char is always thinking two or three steps ahead of the enemy. See them in Mobile Suit Gundam Series.
An assassin with supernatural gifts, Corvo Attano is the last guy you should frame for murder. See them in Dishonored.
A laid-back stoner, Ben Stone wasn't planning on life's ultimate responsibility. See them in Knocked Up.
Don't worry about this forensic scientist offing you unless you're a serial killer yourself. (You're not, right? Just checking.) See them in Dexter.
After becoming accepted into the group of popular girls, Tracy Freeland has turned from a sweet and reserved teenager into a monster. See them in thirteen.