Miroku is a young Buddhist monk who serves as one of the main protagonists in the series. At the age of eighteen when he first appears, he travels the countryside offering spiritual services such as exorcisms and demon exterminations to earn his living. He was raised by the monk Mushin after losing his father and grandfather to a hereditary curse. The curse was originally inflicted upon his grandfather, Miyatsu, by the half-demon Naraku, who exploited Miyatsu's weakness for attractive women. The curse manifested as a wind tunnel, or kazaana, in Miroku's right hand. This wind tunnel is a black-hole-like opening that can suck in anything, regardless of size or mass, and Miroku uses it as a powerful weapon against demons. However, the wind tunnel grows larger with age, and if Naraku is not defeated, it will eventually consume Miroku just as it consumed his ancestors.

Miroku's personality is marked by a combination of lecherous and frivolous behavior and deep inner spirituality. He frequently asks every attractive woman he meets whether she will bear his child, claiming he wants to secure an heir to continue the fight against Naraku if he should die. He is also a skilled con artist who does not hesitate to invent fictional supernatural threats in order to scam wealthy clients out of food and lodging. Yet beneath this hedonistic exterior, Miroku possesses a genuine commitment to protecting others and a profound spiritual core. He is calm, perceptive, and often provides strategic advice to his companions, especially when Inuyasha acts impulsively. He values human life highly and will rush into danger to defend the innocent.

Miroku's primary motivation is to defeat Naraku and break the curse that has plagued his family for generations. This goal drives him to join Inuyasha and Kagome on their quest to collect the shards of the Shikon Jewel and ultimately confront Naraku. Along the way, he seeks to live fully despite his shortened life expectancy, which influences his hedonistic tendencies.

As a member of the main group, Miroku plays the role of both a spiritual warrior and a comic relief. He often lightens tense situations with his irreverent humor, but he is also a reliable fighting ally. His role involves using his spiritual powers to exorcise demons, erect barriers, and attack with sutra scrolls and his staff, in addition to unleashing the wind tunnel. However, the wind tunnel has a significant weakness: it cannot be used against Naraku's poisonous insects, and inhaling poison can harm Miroku himself.

Key relationships define Miroku's journey. He forms a close camaraderie with Inuyasha, the half-demon leader of the group, and respects Kagome's strength and moral compass. His most transformative relationship is with Sango, a demon slayer. Initially, Miroku's flirtations with Sango are part of his usual behavior, but over time their bond deepens into genuine romantic love. Miroku becomes protective of Sango, and his jealousy and commitment to her grow. He eventually proposes to her, asking her to bear his children after Naraku is defeated. Their relationship evolves into a marriage, and after Naraku's death and the lifting of the curse, Miroku and Sango settle down and have three children: twin daughters Kin'u and Gyokuto, and a younger son named Hisui.

Miroku's development throughout the story is significant. He begins as a self-serving, somewhat deceptive monk who uses his curse as an excuse for his womanizing and cons. As he travels with his companions, he learns to trust others and to confront his own vulnerability. His fear of the curse and his desire to leave an heir gradually give way to a deeper commitment to his friends and a willingness to risk everything in the final battle against Naraku. This growth culminates in his marriage to Sango and his eventual role as a father and protector of his family in the sequel series, Yashahime: Princess Half-Demon.

Notable abilities include the wind tunnel, which he typically keeps sealed with prayer beads. He can also generate defensive barriers, exorcise spirits with chanting and talismans, and use spiritual energy to injure demons. His physical strength is above that of an ordinary human, and he wields a staff as a weapon. Despite his sometimes unsaintly behavior, his spiritual powers are legitimate and effective, though not as strong as those of more powerful priestesses or monks. Miroku's name is derived from Maitreya, the future Buddha in Mahayana Buddhism, reflecting his underlying compassion and hope.