A boy named Kaim, whose entire body is tainted by poison, lives as a cursed child. Shunned even by his family, he survives alone — until one day he uncovers the truth behind the mysterious power dwelling within him. When he finally awakens as the King of Poison, he becomes the strongest being in the world — and even captivates beautiful princesses along the way... A tale of an unstoppable poison-wielding hero and his irresistible harem begins!