Kkokdugaksi Daemabeopsa

The crown prince, known as the great wizard, is actually a fake with no power, and behind him is the real great wizard Moa who is with him as a maid. Moa used magic on the crown prince's behalf, not caring about her weakened body due to her love for him her whole life, but in the end, when her body broke down, all she got in return was a terrible betrayal. Just before she dies, in her hazy consciousness, someone extends a helping hand to Moa and proposes revenge on the crown prince... Moa's revenge drama against the crown prince. (Source: Kakaopage, translated)