Neo Angelique is the fourth Neoromance entry and an alternate universe of the Angelique series. Character designs and illustrations were done by Kairi Yura. Maki Fujioka was the character designer for the characters' animated counterparts, both in the game and for the TV series. Character image songs were composed by Yujiro Okazaki. Ruby Party originally devised the game to be a minor side story for the main Angelique series. During the brainstorming sessions for the plot and characters, the members realized that their project's ambitions far surpassed their starting expectations. Therefore, they shifted gears to make an "Angelique title friendly to newcomers", seeking to capture the series's charm without requiring the player to have extensive knowledge of prior lore. Role-playing game elements were devised to take center stage in gameplay due to its popularity in fan surveys at the time. The keywords for this title's narrative are "beautiful, noble, and romantic". The Premium Box included eight postcards, a character message CD and fully colored comic book/manual. Consumers who reserved the game or Full Voice through Gamecity Shopping received a mouse pad with their purchase.

The protagonist is a normal high school girl attending Melrose Girls' Academy in Arcadia. One day, she is visited by a gentleman named Nyx and learns that she has the dormant power to purify Thanatos, or incorporeal monsters that prey on the everyman. She leaves her school life to join Nyx's Thanatos exterminating business: "Aube Hunters". She soon realizes that she is the only female with purification powers because she is the oft fabled Queen Egg, or a legendary savior. Her goal is to work with her fellow Aube Hunters to eradicate Thanatos and restore the land's peace.