It originally started as a novel made by Masaki Okayu. It had nine chapters.
It was later made a manga by Mitsuna Sakuse (I almost wrote Sasuke :P ) for MediaWorks. The manga had 3 volumes.
Afterwards, it was made an animé. It has only two seasons and a OVA. The first season only had 8 episodes and the second one only 4. I haven't seen the OVA, but I feel that it is part of the story because there are some things in the second season that I didn't see in the first one.
WHAT IS IT ABOUT?: The story is about a 13-year old guy called Sakura Kusakabe (apparently, Sakura is a neutral name in Japan, like Ashley in English and Ariel in Spanish.) This guy in the future will create the technology for eternal living, but it makes women to stop growing at the age of 12 because his purpose is to create "the perfect world for pedophiles!!!" :O.
So Dokuro is sent by the Rurutie (an organization of killer-angels) to kill him, but she liked him, so she decided not to kill him and find another way to stop making him a future-pedophile (but she kills him 2-3 times per episode for various reasons with her waepon called Excalibog and revives him with her spell "Pipiru piru piru pipiru pi"). The Ruruties don't like this, so they send another angel, Sabato, to kill him with her weapon called Durandal. She is only seen to try it twice, and fails each tme. The fisrt time, she failed because Sakura took her halo and threw it far far away. You may be right now like "How did that make her fail?" well let me tell you a secret: Taking an angel's halo makes them have the worst diarrhea ever! XDXD.
The second time she failed, was in the movie theatres, Sakura touched Dokuro's boobs so that she waked up and protected him. Dokuro did wake up and instead of protecting him, she gets really mad and throws Excalibolg to Sakura, but he uses poor Sabato as a shield. She recieves the hit and immediatley faints and starts to like vomit a yellow thing. Sakur also vomits the same thing and gets killed by Dokuro, just to be revived by her. Shizuki leaves the room when Sakura gets killed. Shizuki is Sakura's love (and apparently she also loves him).
After that, Sabato leaves Sakura alone and starts to live under a bridge, where a bird steals her underwear XD. After that, you see many funny adventures of Dokuro-chan with Sakura-san until Zakuro appears... Zakuro is another killer-angel and Dokuro's younger sister (but believe me, she looks older than Dokuro... Dokuro is supposedly 13-years old and Zakuro is 9-years old). Zakuro comes to take Dokuro-chan back to heaven because she is charged with treason because she disobeyed her orders. Sakura realizes that he loves Dokuro-chan and promises Zakuro that he'll become gay, EXTREMELY gay so that he doesn't create the technology for eternal life and so that Dokuro stays with him. Zakuro doesn't care and takes Dokuro back to heaven. The next episode (which is the season finale) Sabato helps Sakura to escape Zakuro. Sakura goes home and finds Dokuro-chan, and she kills him "to express her happiness" :P
In the second season, the most important thing is that Zakuro now lives with Sakura and Dokuro-chan.
(Yeah... they're only 9 and 13....) :P
(Make your own opinion) :PZakuro Mitsukai: Dokuro's "younger sister". She is 9-years old, but has the body of a 20+ year old woman. Her weapon is a wet towel (yes, a wet towel) called Ecksilax which is stronger than Dokuro's Excalibolg :O. She is afraid of taking baths alone, so in one episode she takes a bath with Sakura and Dokuro and Sabato afterwards. :P
(Taking away the fact that he's gonna gety killed, isn't he lucky?) :P
Shizuki Minakami: She is this hot girl from Sakura's class that afterwards gives the impression that she is secretly in love of Sakura.
I REALLY HOPE THET DOKURO-CHAN IS MADE INTO A LONGER ANIMÉ, IT'S DEFINITLEY WORHT IT! :D