Plot

Romance the Necronomicon and save the universe from ultimate evil in this Lovecraft-inspired super-robot epic from Nitroplus.

Darkness hangs over Arkham City. Arkham's protector, the young Hadou Ruri, is the only shield keeping the forces of the evil Black Lodge at bay. Amateur detective and former magic student Daijuuji Kurou wants nothing to do with the turmoil, but when Ruri herself shows up on his doorstep with an offer he can't refuse, Kurou is sucked back into the world of supernatural intrigue that he swore to leave behind. His task: to find the key that will unlock the power of the giant robot Demonbane, the city's last hope. your choices will decide the fate of Kurou as he unravels the mystery behind Demonbane, gaining friends, foes, and lovers along the way. Can you harness the power of the dread Necronomicon and save Arkham from the madness threatening to consume it?—JAST USA

Kurou Daijuuji is a poor detective living in Arkham City (no, not that one). A center of both industry and eldritch lore, it is home to Miskatonic University (not that one either), which Kurou is a former student of. The city was built up and is run by an industry group and family dynasty known as the Hadou Financial Group, led by Ruri Hadou, who works to protect the city from the forces of darkness. Her main enemy is the villainous Black Lodge syndicate, led by the charismatic Master Therion. The white-haired Beast of the Antichrist, he is the most powerful sorcerer in the whole world, and his nihilistic outlook shapes the group's destructive goals. One day, Kurou is asked by Ruri to search for a magical grimoire. As Kurou searches for the book, he unexpectedly runs into Al-Azif, a pretty girl who turns out to be the grimoire Kurou is searching for. While being chased by the Black Lodge, Al forges a contract with Kurou, bestowing him with powerful magic. Soon afterwards, Al also activates the Demonbane, a Deus Machina owned by the Hadou Financial Group, to combat the mechanical menace from the Black Lodge and Therion, who seeks the power of the grimore for himself. With this, the war between the Hadou Financial Group and the Black Lodge begins.—TVTropes

Arkham city is a bustling hub of commerce and industry, however Arkham is also a center of eldrich lore: home to Miskatonic University, an institution of higher learning with one of the most complete libraries of arcane literature in the world. In the span of two generations the town was built up to the status of prestige it now commands, an expansion helmed by the Hadou Group, an industrial complex and family dynasty currently run by the young Hadou Ruri. She pursues the peace and prosperity of Arkham diligently, against the forces of darkness threatening to plunge the city, and the world, back into a second dark age. Among the most sinister threats to Arkham City is the evil Black Lodge syndicate. Led by the charismatic Master Therion, his nihilistic outlook shapes the group's destructive goals: with a circle of powerful sorcerers at his command, the potential for sowing chaos in the city is unmatched. Former Miskatonic University Magic Academy student Daijuuji Kurou knows little of grimoires, but what he does know terrifies him - enough that he left his university life behind, and now practices a failing detective business in the shelter of an orphanage in a quiet corner of Arkham. But just when he thought his Academy past was buried, it catches up with him and pulls him back into the dark shadows of the occult: Hadou Ruri herself appears at his door with an offer he can't refuse. The only way to combat the Black Lodge's growing magical power is to find, and retrieve, a grimoire with the power to activate the mightiest Machina of all: Demonbane. The quest to find this forbidden tome will change Kurou's destiny... forever.—VNDB