Two Brothers Conflict OVAs about Christmas and Valentine's Day. New OP and ED songs by the same singers were presented in these two OVAs. (Source: MAL News, edited)

Takuya Arima is a young student whose father, a historian who has conducted various researches, disappeared recently. During a summer vacation Takuya receives a peculiar package from his missing father, along with a letter containing information about the existence of various parallel worlds. At first Takuya doesn't take it seriously, but soon he realizes that he possesses a device that allows him to travel to alternate dimensions. Is his father alive, after all? If so, where is he? (Source: VNDB)

Fifty years ago, mysterious creatures known as the "Huge" suddenly appeared all over the world, posing an existential threat to humanity. To defend against these menaces, soldiers in the form of teenage girls known as "Lilies" use the energy "Magie" within their bodies to power weapons called "Counter Huge ARMS" or "CHARMS." After being saved by a Lily two years ago while evacuating from a Huge attack, Riri Hitotsuyanagi vowed to become a Lily herself. She enrolls in the prestigious academy of Yurigaoka, a training ground for Lilies, and discovers that one of her classmates is Yuyu Shirai—the same Lily who rescued her. Much to her confusion, however, the person she thought to be cheerful turns out to be quite antisocial and prefers to fight alone. Even so, Riri still desires to get along with Yuyu and is willing to do anything she can to reach that goal. With Yuyu and the other Lilies by her side, Riri's journey on becoming one of them has just bloomed! [Written by MAL Rewrite]

Unaired episode bundled with the ninth light novel volume of Kuusen Madoushi Kouhosei no Kyoukan.