Milk Arara, also known as Arara Miruku, is a central heroine in the NG Knight Lamune & 40 series. Initially appearing as a video game peddler in the human world, she encounters protagonist Lamune. After he purchases and completes her game, Milk emerges from his television, revealing her true identity as Princess Milk from Hara-Hara World. She recruits Lamune as the "Blood Relative of the Chosen Hero Lamuness" to aid in reviving the Guardian Knights and defending her realm.

As princess of the Kingdom of Arara, she holds royal status; her older sister Cocoa Arara is second-in-line to the throne. Milk actively guides and supports Lamune throughout their adventures in Hara-Hara World, frequently joining missions and confrontations against antagonists like Don Harumage. Her relationship with Lamune evolves significantly.

In the sequel VS Knight Lamune & 40 Fire, Milk and Lamune (now Ramune) are married and deeply committed. Operating under disguised identities to avoid attention, they wear costumes resembling parodies of Gatchaman characters – reportedly designed by Milk as their wedding attire. Their affectionate married life includes their son, Baba Lamunade, who becomes the new protagonist. They occasionally emerge from retirement to offer guidance or assistance during crises.