魔王様と砂時計～転生したら妖精さんで将来の魔王に病まれる話～

Synopsis

The genius boy who is destined to become the final boss demon king loves me, who has been reincarnated as a fairy. Louis, a boy with a talent that surpasses adults as a court magician, lives with his sickly sister and one day catches a fairy in the forest. It is Eleanor, a girl who has been reincarnated in another world as the hero's fairy in this otome game. The palm-sized girl lives in a cage. However, by drinking Louis' blood, she can change to the size of a human woman...? Louis pours his sick love into Eleanor. What is the true purpose of this handsome and promising boy in this world?