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

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

Araki, Hirohiko

The creator of Baoh and JoJo no Kimyou na Bouken presents a manga about magic and mysteries! You'll meet him at 13:13 pm, on Friday the 13th. He'll do an uncanny intro where he plays a trick on you! And wherever he goes, trouble seems to always follow. Who is this person who creates such incidents? None other than Cool Shock BT!

(Source: Project Bite Me! Scanlations)

Mashounen B.T.

Cool Shock B.T.

魔少年ビーティー

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.

Fushigi Hunter

不思議ハンター

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

Takada, Yuuzo

Through a strange series of events, a young man named Yakumo Fuuji becomes the immortal slave of the last of a race of 3 Eyed immortals. The immortal, Pai, absorbs his soul to save his life, making him immortal in the process. Now, he begins a journey with the female immortal in an attempt to find a way of becoming human. Of course, there are many complications along the way, not the least of which being that the immortal is a female with a split personality, one achingly cute and the other being no-nonsense destructive power, and romances that develop between.

3x3 Eyes

3×3 EYES

Hamada, Shoko

Kuwabara, Mizuna

Toujou, Kazumi

Mirage of Blaze is equal parts melodrama, historical romance, and supernatural fantasy. Japanese history predominates a heavily structured plot, which mainly involves the continued aggression between magic using guardians, or "possessors," and the denizens of a "feudal underworld," or the restless souls of long-dead samurai attempting to re-ignite ancient war on the modern plane.

Honoo no Mirage

炎の蜃気楼〈ミラージュ〉

Robi~na

Fate/Extra

Fate/EXTRA -フェイト/エクストラ-

Yasuhiko, Yoshikazu

The young Arion is tricked by Hades and is taken to the underworld where he is trained to become a warrior strong enough to defeat even a god. Thrusted into a war among the Titan brothers, Arion embarks into a colossal saga towards the Olympus, home of Zeus.

This is the story of Arion, a little boy raised by only his blind mother in a barren land. One day a man comes to visit his mother. This man calls himself Arions uncle and Arions mother calls the man Hades. The uncle convinces Arion that he knows where Arion can get a hold of a special herb that can cure Arions mothers eyes, and so the boy willingly comes with his uncle Hades on a journey. The moment Ariona agrees to go, his mother feels it in her heart and rushes out of her little house and screams at the sky ; Zeus, your brother is taking Arion to the land of the dead. Follow Arion on his adventures among old greek gods and godesses.

(Source: ANN)

Arion

アリオン

A collection of stories released to celebrate the 50th anniversary of Go Nagai's career.

Gensen Tanpenshuu: Gougasha

幻選短編集 豪画沙 GOGASHA

Ogino, Makoto

A young mystic without a past, Kujaku was born under a dark omen possessed of incredible supernatural powers. Raised by priests, he has learned to use these powers for good. But the evil Siegfried von Mittgard seeks to steal his birthright, and rule the world as the Regent of Darkness. He has dispatched bloodthirsty minions to destroy Kujaku before he can awaken to his destiny. Now, Kujaku must unravel the riddle of his past, before the power within consumes him!

(Source: AniDB)

12 Manga Like Ao no Exorcist