Otaku siblings Tamotsu and Niwaka Denkigai are shopping in Akihabara when it is overrun by vampiric cosplaying monsters! These creatures, known as "Bugged Ones," can possess anyone they bite and soon they begin causing mayhem across the city. As Tamotsu finds himself at the mercy of one of these creatures, he is rescued by the mysterious baseball bat-wielding Matome Mayonaka. Together, they fight through several more encounters with the Bugged Ones, but before long, Tamotsu is fatally wounded protecting Matome. With no other choice, she revives him as a high level Bugged One—just like her! Tamotsu and Matome, along with excitable otaku cosplayer Arisa Ahokainen, make up the group "The Electric Mayonnaise" and they begin dispatching the Bugged Ones in the only way they know how: by ripping off their clothes and exposing them to sunlight! [Written by MAL Rewrite]

Mysterious Babylonian Tablets unearthed in Manhattan provide tantilizing clues about the location of the Tower of Babel - not the biblical one, but the original one, built out of solid gold! 

The Mob is out to get the gold, but so is Lupin III. 

It's Thugs vs. Thieves when Lupin & Co. go up against a fearsome flyswatting Polish Mafia boss, a bevy of beauty-contest policewomen, Zenigata, the hard-luck Interpol Inspector, a mysterious bag-lady AND his own girl-friend in a trans-continental trust-nobody trek after a treasure of biblical proportions! 

(Source: AniDB)

Kurou Daijuuji is a poor detective living in Arkham City. One day, he was requested by Ruri Hado of Hado Financial Group, to search for a magic book. While he initially refused, Ruri offered him a large sum of money upon completion of her request, in which bribed Kuro to accept. As Kurou searches for the book, he unexpectedly runs into Al, a pretty girl that is actually a powerful grimoire. They forge a contract with each other, bestowing Kuro with powerful magic. Soon afterwards, Al also activates Demonbane, a deus machina owned by the Hado Financial Group, to combat the mechanical menace from the Black Lodge. With this, the war between the Hado Financial Group and the Black Lodge begins.... (Source: ANN)

Takaya Ougi is just a typical high school guy who wants nothing more than to protect his best friend and live a normal life. Enter Nobutsuna Naoe, an older man who informs Takaya that he is in fact the reincarnation of Lord Kagetora. Naoe, himself a possessor, awakens Takaya's abilities to exorcise evil spirits and fight the Fuedal Underworld. While most possessors remember their former lives before being reincarnated, Takaya does not. Naoe is thankful for this, considering his passionate and abusive past with his Lord Kagetora. As Takaya improves his abilities, he also begins to remember what Naoe did because of his love for him. Meanwhile the dark forces of the Hojo and Fuma clans begin their attack as the Fuedal Underworld descends upon the living world.