Milly Yunis is a supporting character in the anime The Legendary Hero Is Dead! She is the younger sister of Yuna Yunis and a childhood friend of the protagonist, Touka Scott. At sixteen years old, she is a spirited and courageous adventurer who wields the artificial sacred sword Durandal, a weapon she obtained by defeating formidable enemies. Though she is not the chosen legendary hero, she carries herself as a second hero and travels under that self-proclaimed title.

Her personality is fiery and battle-hungry, and she often challenges Touka to one-on-one fights. This stems from a childhood promise between them: whoever wins a hundred bouts will marry the other. She is upbeat and bubbly, and unlike her sister who frequently grows annoyed at the bizarre antics of the group, Milly seems comfortable with such behavior. Her motivations are driven by a desire to prove her worth as a warrior and to raise funds for the reconstruction of her homeland, Elbania.

In the story, Milly serves as a major supporting character who brings additional combat strength and a competitive dynamic to the party. Her key relationships include her bond with her elder sister Yuna, with whom she shares a close but occasionally exasperated connection, and her playful rivalry with Touka, which is founded on their shared history. While she does not undergo a major character arc within the anime, she remains one of the most action-driven and spirited members of the cast. Her notable abilities include her skill with the artificial holy sword, which, while not capable of sealing the Gates of Hell like the true hero's sword, is highly effective in dispatching demons.