In Killer 7, players take on the role of Harman Smith an unlikely assassin who leads a life as the intermediary link between seven alter egos. Switching between his seven different personalities, Harman employs each character's unique abilities to terminate targets he deems "deserving to die." Now a powerful underworld kingpin has unleashed violent creatures called 'Heaven's Smile.' These crazed soldiers, affixed with horrific smiles, have started to wreak havoc on city streets. It is up to the player to interchange Harman's seven 'partners' and utilize the special powers that dwell within them in order to assassinate Kun Lan, the notorious criminal overlord behind all the madness.

1. Distinctive and visually stunning, post-modern approach to cel shaded environments
2. Unique cast of playable characters – Each persona has different strengths, special abilities and weapons that help Harman proceed through the game.
The seven personalities that comprise the "Smith Alliance" include:
3. Garcian Smith – The clairvoyant leader of the 'alliance' who has the ability to turn invisible and serves as the "cleaner" that recovers the bodies of fallen teammates
4. Dan Smith – Strong and extremely well trained, Dan has the ability to wipe out the enemy with his fiendish destructive force
5. Mask De Smith – A grenade launcher wielding man who is unbeatable with his specialty wrestling moves, countering any attacks brought upon by his enemies
6. Coyote Smith – Has the ability to unleash a frighteningly destructive "Gang Kick" that can knock down enemies with a single blow
7. Kaede Smith – The only female personality of the group. She throws her enemies into confusion by blasting out a shower of blood super-charged with a deadly virus
8. Con Smith – A young man blessed with exceptional hearing. He uses his ability to reveal the locations of hidden items
9. Kevin Smith – An independent personality that keeps to himself. He can eliminate a target with ease using a number of masterful knife wielding techniques