Ep. 12: Holy Seal and a Vampire
After the incident involving Lilith's Mirror, the barrier dividing the two worlds begins to crumble since the rosary stored in the academy that seals the monster energy from leaking out has now been cracked in response. Moka decides to make the ultimate sacrifice by replacing the broken rosary on the seal with her own rosary. As a result, Moka's outer self pays the price of being permanently replaced by Moka's inner self. Throughout the day, the other girls have a hard time getting used to Moka's inner self, while Tsukune cannot help but have Moka's outer self on his mind. Though Mikogami orders her not to tell anyone, Ruby tells Tsukune at night how to recover Moka's rosary, but also warns him of how dangerous this task may be. Tsukune must find the third of the three dark lords who crafted this relic, all of whom founded the academy and built the barrier, that resides in a castle north of the barrier. Kokoa overheard this conversation between Tsukune and Ruby and is planning to intercept him before he reaches his destination. (Source: Wikipedia)