Nagai, Go

Soft-hearted Akira Fudou has always been somewhat of a pushover. When he reunites with his childhood friend, Ryou Asuka, in a fateful encounter, Ryou reveals to him the terrifying reality of his father's research: demons exist and are planning to claim possession of the earth once again.

Eager to help his friend save humanity, Akira agrees to attend Black Sabbath, a party filled with depravity and corruption, to attempt to merge with a demon. A near-death encounter causes him to unify with Amon, a demon feared amongst even his own kind. Together they form Devilman, a combination of Amon's strength and Akira's pure heart.

After uniting with Amon, Akira begins to fight against the demons with his newfound power, desperate to stop the downfall of all human civilization.

[Written by MAL Rewrite]

Devilman

デビルマン

Adachi, Mitsuru

The story is set in a place very similar in appearance to Earth in the Edo period. However, Adachi (the mangaka) regularly reminds the reader all throughout the series that the setting is another planet in the distant future which just happens to look like Earth.

After the death of his mother, Shichimi sets out to join his step-brothers and -sister who live together in Karakuri Tenement, a place provided by the father they have never met. He finds out that each of them had different mothers (all of whom have died), but were fathered by the same man. Not long after Shichimi's arrival, the siblings decide to journey to visit the graves of each of their mothers. On this journey, they encounter many dangers.

(Source: Wikipedia)

Nijiiro Tougarashi

虹色とうがらし

Manabe, Jouji

It`s face-to-face confrontation when Kahm stares down her father and refuses to end her relationship with Tetsuya. In retaliation, her father sends a punitive fleet to Earth -- with orders not only to crush the rebellion but to annihilate the entire solar system!

(Source: Amazon)

Outlanders

アウトランダーズ

Shirow, Masamune

The main plot revolves around the Yamata Empire's plan to destroy all the galaxy's negative karma  using a massive technological reactor called the Nāga Generator. Unfortunately, negative karma cannot simply be destroyed, it must be atoned for. However the leader of the powerful mystic Buddhist Fuze Clan plans to stop the destruction of the negative karma which will end up creating the nine-headed Nāga and destroy the world if not the whole universe. To help in stopping the creation of the Nāga, the clan summons a Shinto god known as Susano, the Warrior God of Destruction. The powerful, arrogant, and homicidal god faces challenges. These include the Empire and the clan leader's own daughter, the bratty sorceress Seska, who is possessed by the power of the negative Karma and a powerful magic formula.

(Source: Wikipedia)

Senjutsu Choukoukaku Orion

Orion

仙術超攻殻 ORION

Obata, Takeshi

Sendo, Susumu

In a world where djinn rule and humans are enslaved, Toto and Loukir break the seals of the century-old prison of the "gentle genie," Rampou, in order to try and save their country...

(Source: Deja-vu)

Arabian Lamp Lamp

魔神冒険譚〈アラビアン〉ランプ・ランプ

Oze, Akira

The story tells about Hiroshi Shiba, a car racer who is mortally wounded on a laboratory accident, but restored to life by his father, Professor Shiba, a talented scientist/archeologist, who is incidentally investigating the relics of the ancient Yamatai Kingdom. The professor discovers a tiny bronze bell with sorcerous powers, and shortly afterwards he is murdered by the henchmen of Queen Himika, the ruler of the Yamatai (sometimes translated as Jamatai) Kingdom, who wants to seize the ancient bell and its power.

Koutetsu Jeeg

鋼鉄ジーグ

Tezuka, Osamu

Collection of various short stories. 

(Source: M-U)

Tiger Books

タイガーブックス

Matsumoto, Leiji

Collection of short, humorous stories by Leiji Matsumoto.

Wadachi

ワダチ

Shibata, Masahiro

Komatsuzaki Ran is not a normal girl. Raised by wolves, psychic powers, the ability to turn into Akai Kiba (The Red Fang)...and a lot of people after her.

(Source: MU)

Akai Kiba: Blue Sonnet

紅い牙 ブルーソネット

Uno, Hiroshi

At the end of 19th Century, Captain Drake, the pirate who traveled all over the world died. Rumor has it that he hide his treasure that is worth thousand millions pounds away from people. The map to this treasure is being torn into 2 parts. One part of it is owned by the military, lead by Colonel Visconti. The another part is owned by Drake's son. 

That young boy's name is Captain Kid, and with his Black Lightening sword and Kid's cunning crews the journey to find Captain Drake's hidden treasure begins.

Captain Kid

キャプテンキッド

Kusunoki, Kei

Jinnai, an enthusiastic cop is now at lost. First a gruesome murder case he's working on is assumed by people that it is a work of a demon. Then, his unit is getting help by a special agent sent by FBI to solve this case. What kind of special agent? An agent that specifically know how to handle Demon? Great! And that agent is just a high school girl? What does her unit called again? G-man.

Things get more complicate when the witness of the crime is also a beautiful woman and now both of them fell in love with him. Jinnai tries to be strong but will he be able to resist them? Not to mention another G-man who fell in love with that high school girl? Will Jinnai handle all of this mess and solve all cases concerning demonic entity at the same time.

Daitokai ni Hoero

大都会にほえろ

Kuroiwa, Yoshihiro

Iizuka, Yukihiro

Raimon Ryuuta and Kuuko are sibling. Their parent is a treasure hunter, so since they were little they lives in a shrine with their parent's best friend who is an old man.  

Ryuuta and Kuuko are interested in anything strange, curious issues. Together they set up their business as a Fushigi Hunter, to solve cases of strange paranormal activity people asking them for help.

12 Manga Like Geobreeders