Kite

Sawa is a school girl, an orphan, and an assassin. She is being controlled by a corrupt cop who gives her targets to kill, detailing to her the crimes these men have committed in order to justify their death. Some of his power over Sawa has to do with her deceased parents and the promise of revenge. When another orphan, a teenage boy called Oburi, is brought in to assist Sawa, the two teenage killers form a bond of sorts. As they heal each other's emotional wounds, they begin to dream of a life that would not be spent under the shadows of murder.

(Source: Anime News Network)

Note: Originally released in Japan as a 2-episode OVA, the series has seen numerous re-edits and releases that exist in several versions:
Japanese Releases:
• A KITE, released February-December 1998 - Original 2 episode OVA.
• A KITE INTERNATIONAL VERSION, released July 2000 - Re-edited version combining the episodes into a 45 minute OVA and removing the sex scenes entirely.
• A KITE PREMIUM COLLECTORS VERSION, released December 2007 - Bundle containing both Vols. 1+2 and INTERNATIONAL version.
• A KITE Special Edition, released April 2015 - Digitally restored Blu-ray re-release with smaller censorship mosaic.

North American releases:
• Kite, released April 2000 - Based off of the international version, the sex scenes are removed entirely and presented as 1 combined episode.
• Kite: Director's Cut, released January 2002 - Released on Media Blasters' Kitty Media (Adult) label, restoring the sex scenes, save for ~12 seconds of material involving sex with a minor, also presented as 1 combined episode.
• Kite: Special Edition Uncut, released September 2004 - Also on Kitty Media, restoring the previously removed footage and presented as 2 episodes like the original.

For simplicity sake, we are only counting the first OVA release in this entry.