Ifrit: Danzai no Enjin

Ifrit ~A Burning Man's Conviction~ (イフリート～断罪の炎人～) is a shōnen manga by Masanori Yoshida. The manga ran in Shōnen Sunday from 2007's issue 2/3 to 2008 issue 40. Yoshida created a prototype version of the story which debuted in Shōnen Sunday 2004 issue 43. Instead of developing the story after its short story debut, Yoshida serialized Grandliner instead.

Plot
On the surface Yu and Minami are very typical; they work at a coffeehouse and live mundane lives. What most people do not know is that Yu and Ninami are both assassins with supernatural powers. As they carry out their contracted kills, they search for the people responsible for the alteration of their bodies.

Characters

 * Yu (ユウ)
 * An assistant to Genzaburo Kujo for the first half of the series and an independent assassin for the second half, Yu relies on the heat generated by his body and a natural talent in the martial arts to kill. Yu's body was heavily augmented after being rescued as the sole survivor of a plane crash and used as an experimental subject. His body can to heat up to nearly 1000 degrees (and higher with training and the right equipments). Because of this he relies on Ninami to keep his body cool, in hopes that he can live long enough to have his body returned to normal and exact revenge on the head of the experimental project. Due to his unusual body, he has to sleep inside a refrigeration device and wear special clothing that controls the amount of heat released.


 * Ninami (ニナミ)
 * An assistant to Genzaburo Kujo for the first half of the series and an independent assassin for the second half, Ninami relies on lowering her body temperature to kill. Throughout most of the series, her body temperature can reach -200 degrees, causing her entire body and everything around her to freeze. In order to stay alive, she depends on Yu to keep her body from growing too cold for most of the series. She must sleep inside an oven to keep her body temperature up and wear special temperature-control clothing when going out. However, Ninami differs from Yu because she is a 'natural-born', just like the individual who gave Yu his fiery power. Because of this, she was able to develop her full power near the end of the series to a degree far greater than that of Yu's and no longer requires Yu to keep her warm. After her full power has been awakened, she is capable of not only lowering temperature, but controlling it completely within a certain range, namely, from absolute zero to above 0 degrees Celsius.


 * Genzaburo Kujo (九条 源三郎)
 * Kujo runs the coffee shop where Yu and Ninami work. He returned to the underworld after leaving 10 years earlier. He is the assassin who officially receives the contracts, but relies on Yu and Ninami to fulfill the objectives for the first half of the series, as he has 'lost' his talents after holding his baby granddaughter. As a skilled hacker, he assists Yu and Ninami for the first half of the series. In the second half of the series, he regains his former talents, once again becoming one of the best gun-fighters in the underworld, capable of staggering feats such as dodging bullets at point-blank, redirecting bullets in flight, and completely perfect marksmanship.