Onechanbara Z2: Chaos

The Banefuls and the Vampirics are two ancient rival demonic bloodlines. After the numbers of both factions dwindled to almost nothing it was thought that the blood feud was over. After the Vampiric sisters Kagura and Saaya defeated their treacherous adoptive mother, the Vampire Queen Carmilla, at the end of the last game, aided from the shadows by Aya and Saki, two legendary zombie-hunting sisters of Baneful Blood, the truce came to an abrupt end and the two sets of sisters could restrain themselves no longer.
Carmilla's throne room became a battleground once again as the two pairs of sisters battled for supremacy. The battle, however, was undecided, as the floor beneath them collapsed sending the four into the abyss below, but not before glancing a mysterious, slender, green-haired woman now sitting in Carmilla's throne. The girls become separated from their respective sisters and are pushed into uneasy alliances for survival. In the catacombs beneath the castle, Kagura is forced to drink Aya's blood in order to regenerate after she is critically injured by demonic moles being kept in the castle's depths. The fusion of the two bloodlines within Kagura's body allows her to temporarily transform into a powerful new form, Dare Drive, slaying all who stand before her.
Saaya and Saki are thrust into a pocket hell dimension but are able to escape by co-operating to defeat the waves of undead blocking their exit. They escape to the castle village but are attacked by a masked undead assassin known as Misha. Misha bests the girls and seriously injures Saaya. Kagura and Aya reunite with them and advise Saaya to feed on Saki's blood in order to recover and transform into her own Dare Drive. This works, and the four girls work together to force Misha to retreat and slay her undead entourage. Now working together, the girls are advised by their friend Anna of the Zombie Prevention Force (ZPF) to wipe out several zombie outbreaks around the world and eliminate several high-profile targets. The attacks are revealed to be diversions to keep the girls at bay whilst Misha locates the ZPF Headquarters and slaughters and zombifies the personnel within. Fortunately, being a field operative, Anna is absent and evades the attack.
The four girls arrive at the scene where the results of Kagura and Saaya's vampiric bites finally take their effects on Aya and Saki's Baneful bodies, granting them similar transformations known as Xtatics. The four cut their way through floor after floor of zombified ZPF whilst chasing Misha. On the rooftop, the green-haired woman escapes by helicopter, leaving the party to battle Misha. With their enhanced abilities, the girls are able to defeat Misha once and for all. The mortally wounded Misha falls from the rooftop as her mask shatters, revealing that she was in fact Misery, a rival Baneful and loose ally of Aya and Saki's late nemesis, Himiko. Misery was slain a year previously by Aya and Saki to end her insane bloodlust and was subsequently resurrected by the green-haired woman.
Anna contacts the party with news that the green-haired woman has returned to Carmilla's castle. The girls follow and attempt to evade the awaiting zombie army by navigating a network of tunnels. Despite many traps set for them, the girls successfully confront the green-haired woman in the now restored throne room. The woman identifies herself as Evangeline, or 'Evange' for short, and reveals her goal of creating a world for both the Banefuls and Vampirics; a world she aims to create by fusing the bloodlines, much like the party did previously. Evange offers the girls a place in her utopia, but soon withdraws her offer when she realizes the girls still intend to kill her. Evange attacks the party, using her own fused blood to transform, but the party emerges victorious and slays her.
The girls agree to put the ancient blood feud behind them and make their alliance permanent. Later, Anna contacts the girls and reveals Evange's origins. Evange was a researcher working for Carmilla who used the castle's facilities to further her own cause. She was also Misery's older sister.