Manga: Descendants of Darkness aka: Yamino Matsuei
From left to right: Watari, Saya, Tsuzuki, Hisoka, Yuma and Tatsumi.
Asato Tsuzuki is a shinigami who has been working in the afterworld for 70 years (with a low wage), investigating cases related to unnatural deaths. Although he is very capable, he is constantly in trouble because of his laid back and spacey attitude, and his inability to retain a partner. Things seems to improve when Tsuzuki is assigned to work with the new shinigami Hisoka Kurosaki, a teenager with a very serious attitude, in contrast with Tsuzuki's playfulness. Unfortunately, in their first case together they cross paths with the insane Doctor Kazutaka Muraki, a man who has gotten supernatural powers in very questionable ways. The doctor is involved in a lot of dirty business (including the death of Hisoka), and now wants Tsuzuki...Began as a manga in 1997 and was made a 13 episode anime in 2001. The author took a hiatus in 2003, leaving the series unfinished until January 2010, in which volume 12 was released. The series is, however, being continued as of recent notification.
This series provide examples of:
Adorkable: Tsuzuki, so much. A grown man shouldn't be so moe.
Affably Evil: Muraki is a polite doctor who approaches one in the most sympathetic manner when he is not raping, cursing and killing 13 year old boys or conducting human experiments to bring back his dead brother to life so that Muraki can be the one to kill him the second time.
Almighty Janitor: Tsuzuki is stuck in a department where he won't do much damage, but is singlehandedly one of the most powerful shinigami in the Bureau.
Art Evolution: The manga and characters — especially the male characters — start out damn pretty, then through the first eleven volumes became drop-dead gorgeous and sexy. In the newest installments, the art changed noticeably once more, possibly because of health issues with the author. Character designs have become distinctly crude and blocky compared to earlier artwork, but remain highly detailed nonetheless.
Big Eater: Tsuzuki has a very big sweet tooth, and spends all his money on food.
Blond Guys Are Evil: Muraki fits the character type to a T though his hair stretches the lightest limits of "blond".
Bluff the Impostor: When Hisoka suspects that Tsuzuki is possessed by a demon, he proves it by asking Tsuzuki to go get food for the group and "reminding" him that the Chief hates sweets. In reality, the Chief has a notorious sweet tooth, so when Tsuzuki falls for it, Hisoka's suspicions are confirmed.
Boke and Tsukkomi Routine: Tsuzuki and Hisoka. The rest of the bureaucrats create different dynamics that usually end up in the same comedic routine. And then there's Muraki.
Cast Full of Pretty Boys: The average female character has the life expectancy of a particularly stupid gnat or falls off the face of the earth after only one or two appearances, and only one major character is not a bishonen.
Creepy Cool Crosses: In the anime, Muraki is first seen kneeling in a church with the large shadow of a cross falling over him, which plays up his angel-like appearance; later he monologues about Christians in the Tokugawa era carving crucifixes on the backs of Buddha statues to conceal their faith (this accompanied by an image of Kwan Yin which looks oddly like a statue of the Blessed Virgin).
Distress Ball: This gets passed around a bit, but is often picked up by Tsuzuki. He really shouldn't get into as much trouble as he does because of his powers, but he tries to never hurt others so he gets hurt instead.
Distressed Dude: Most often Tsuzuki, because of his need to help others and pacifism.
Driven to Suicide: Tsuzuki, when he was alive, because he felt that his existence could only bring pain and suffering to those around him. He tries it again later. Hisoka hugs him out of it.
Faking the Dead: Hisoka dresses up as Hijiri and lets the demon possessing Tsuzuki butcher him to trick said demon into thinking that Hijiri is really dead. He gets better. Muraki also poisons himself with low dosages to be able to handle a paralysis serum a la Romeo and Juliet.
Friend to Psychos: Mibu Oriya, an old friend of Muraki. He covers up for Muraki, gives him a place to stay, and even disposes of the bodies sometimes.
Gecko Ending: Muraki's mother and Saki. Completely different stories, between anime and manga, which changes Muraki's characterization quite a bit.
Gender Flip: Word of God, as in the manga, it is directly stated that originally several of the characters were going to have opposite genders than what they wound up as!
Genre Shift / Out-of-Genre Experience / Breather Episode: The first three volumes can be pretty consistently placed in the supernatural detective/thriller genre, with liberal dosings of horror. Cue volumes 4 and 5, in which the main characters visit a hot spring and rescue a missing ice queen who went missing because she was KO'd by a badly-cooked muffin and have an epic inter-departmental archery contest. Oh, and then Tsuzuki is sucked into magical storybook land where he meets his genderswapped self. After a few volumes of these sorts of situations, the series goes right back into the horrific murders. A few volumes later, a magical shonen adventure plot starts up.
Good Thing You Can Heal: Muraki to Hisoka in the first volume, after covering a room in his blood and torturing him at length. He even contemplates vivisecting Hisoka to test out how strong his regeneration abilities really are.
Gorn: Thanks to the shinigami Healing Factor, the main characters get torn to pieces repeatedly and the results are splashed across the page in great detail. Some examples:
When disguised as Hijiri, Hisoka gets hacked nearly in half and his eye is pulled out.
The gruesome reveal of several murder victims on the cruise ship in volume 3 especially the dismembered corpse of Tsubaki's father
In volume 4, a young Catholic schoolboy comes back as a rotting corpse (who proceeds to slurp out the organs of a priest).
Hates Being Touched: Hisoka, no doubt as a result of several factors including his abusive family who shunned him because of his empathic abilities and the deal with Yatonokami, as well as his ability to read people's thoughts via the emotions triggered from them and also from being raped and murdered by Muraki.
Healing Factor: All of the Shinigami, although they can be killed by hellfire, as shown by Tsuzuki's suicide attempt.Extreme in Hisoka's case.
Incest Subtext: A shorter story in volume 2 of the manga has Tsuzuki ballroom dancing with a professional... and keeping pace with her. At one point he tells her that while her technique is flawless, she doesn't "share" the dance, and that he "can't teach her." In his words, "It means dancing as though you're in love with your partner... Dance like you want me!!!" A page before this, he stated it was his sister who taught him how to dance with such... um... passion.
It's even foreshadowed and simultaneously lampshaded by Hisoka, who wonders what Tsuzuki's family was like.
To make it even more suspect, it's heavily implied Tsuzuki falls in love with Hisae... because she reminds him of his sister. Later when Ruka appears in the manga, she looks very similar to Hisae...
Mad Eye: Somewhat averted in Muraki, since he has an artificial eye, but it only adds to his air of insanity.
Mad Scientist: Watari is a kind version of this trope, complete with Mad Scientist Laboratory and an interest in Gender Bender. Dr. Muraki, the insane evil version, is also fond of research labs and keeps the severed head of his dead brother alive in a clone tube.
The Magic Poker Equation: When Tsuzuki plays Muraki in a game of poker, he loses with a flush to Muraki's full house. When Hisoka plays against Muraki, he beats Muraki's four of a kind with a royal flush.
Mama Bear: Suzaku to Tsuzuki, in a particularly dramatic fashion in the Kyoto Arc.
Omnidisciplinary Scientist: Watari is made of this. The manga shows him as being unbelievably proficient with hacking and decryption, involved in maintaining the computer-based reality where the series' summoned gods live, and good enough at chemistry for potion-based Mad Science (which could also be partly magical), and he's alluded to having done other things. His PhD? In Mechanical Engineering.
One-Book Author: Yami Matsu is Matsushita Youko's only series so far, though she did publish an unrelated one-shot in a magazine once which was never released in tankobon form.
You Killed My Father. Prepare to Die: Kijin is determined to fight Kurikara and erase his existence from all of Gensoukai because he attacked and injured Souryuu, Kijin's father. Kurikara is actually innocent; Futsu, his right-hand sword, acted on its own. Not that anybody knows that.