Shin Koihime†Musou: Otome Tairan OVA.

Handsome and effeminate, quiet but proud, the sinister Akito Kobayashi has a passion for the occult and has developed a computer program to summon demons and the living dead. But little does he know that fellow high school students Kojirou Souma and Saki Yagami are reincarnations of powerful and benevolent spirits. When the pair's friends have become targeted by demons trying to harvest their life energies, they must harness their dark metaphysical powers to destroy Kobayashi's threatening program, or risk losing their loved ones forever.

In 1941, one year after the defeat of Sotetsu Genan, captain Seijuurou Kamiyama of the Imperial Combat Revue's Flower Division in Tokyo leaves on a secret mission, with Sakura Amamiya temporarily assuming command. Following an incident in Europe, Kamiyama takes a young Russian girl named Klara M. Ruzhkova and leaves her in the Flower Division's care. However, Moscow Combat Revue captain Valery Kaminski is sent to Tokyo to retrieve Klara and the Flower Division must stop him. (Source: Wikipedia, edited)

Set a few months after the original series, Wataru is called into action once again!