Kikou Majutsushi: enchanter

Fulcanelli, an ancient engineer and alchemist capable of infusing his creations with magic, became a demonic entity after his death and is now partnered with Eukanaria, his demon lover. He requires a new body, and Eukanaria must protect the pendant holding his soul from those seeking his power. In the modern era, Haruhiko Kanou is a normal boy skilled in machinery and has a crush on his science teacher and neighbor, Yuki Fujiwara. Unaware of his significance, he is identified by Eukanaria as a suitable match for Fulcanelli.