Read manga: Doors Of Chaos

manga
Summary:

When all the doors open, the world will slip into chaos... Only the twins Clarissa (open) and Mizeria (close) control the Four Doors that protect the world from descending into chaos. When Rikhter, their guardian, kidnaps Clarissa, he weakens the Door of Chaos and demons begin to pour through, threatening to destroy the entire kingdom. Will Mizeria find her sister in time to close the door and restore order to the world? (Source: Tokyopop)