OVERVIEW
He is a houshi (Buddhist monk), who possesses a rather unusual curse. His right hand has a slowly expanding Kazaana ("wind void"; "Wind Tunnel" in the English dub) that sucks in anything nearby if it's not kept covered by a cloth and strand of japa mala beads. This curse was placed on Miroku's grandfather by Naraku and passed down to him. His father died because the wind tunnel grew so large that it sucked him up. Eventually, the curse will cause Miroku to be sucked in as well, unless Naraku is defeated, and the curse is broken. He is, therefore, one of the main reasons the group is after Naraku.
Miroku meets InuYasha and his friends after walking away from a town after cheating a rich man there out of some money. While bathing in a hot spring, he sees Kagome naked, also taking a bath. He discovers she has shards of the Shikon no Tama (The Jewel of Four Souls) while staring at her and takes them (the jewel shards) and her bike (which he somehow knows how to ride) with the help of his tanuki friend, Hachi. InuYasha and Kagome catch up to him and InuYasha attacks him, but Miroku uses his Kazaana in return. Kagome, realizing that the monk will not harm humans, stands in its path and causes Miroku to quickly cover it with his prayer beads. Miroku explains his situation, and InuYasha reluctantly allows him to join them.
Miroku has habit of asking countless, random women to bear his child, which is formally known as womanizing. He does this because if he would happen to die while in the process of killing Naraku, he would want his son to finish the family mission. Despite his good looks and temperament, Miroku's worst vice (and best running joke) is lechery, specifically shameless flattery and occasional groping with varying subtlety. He is a big flirt that always asks seemingly single women to bear his children. It is known that he had a foster father, grandfather and father, but no trace of a mother. Miroku must have a child in order to have an heir by the time he may be killed by the curse, and thus finds it perfectly fine to offer the chance to many young women to bear his child. This lessens, but does not disappear completely, after he becomes engaged to Sango.
In fact, it was lechery that got Miroku's bloodline into trouble in the first place. His grandfather was fooled into "caring" for a young woman, who turned out to be Naraku in disguise. It was then that he received the Kazaana curse. Despite knowing this, Miroku continues his ways. As an ironic twist of fate, one episode of the anime lands Miroku in a similar situation where he woos a young woman who turns into an insectoid youkai. His Kazaana suffers a dangerous rip before he destroys the youkai, forcing him to seek medical attention from his old caretaker, Mushin.
Nonetheless, the monk mellows out as time goes on and proves to be a very valuable ally. He is very knowledgeable about youkai, and is the secondary fighter of the team after InuYasha. Though quite possibly the most intelligent of the group, Miroku often uses humor or lechery to lighten serious situations, especially if anyone is worried about him. Despite his lighthearted and lecherous exterior, it is clear he has an inner darkness (Shippo has been heard to comment that he "never bought that holy man routine") and worries over his curse and the resulting death sentence that hangs over his head.
POWERS AND ABILITIES
Demonic power:
Kazaana (English: Wind Tunnel): Miroku has a void in his hand that can suck anything in. Exactly to where it leads the matter it absorbs can be anybody's guess. Miroku's grandfather was cursed by Naraku with the void in his right hand, and it has passed on to his father (who, according to the anime, was absorbed into his own Kazaana right in front of Mushin and a child Miroku) and now him. As time passes the hole grows in size, and thus increases in power. If Naraku is not destroyed in time, the void will eventually breach the confines of his palm and Miroku will be drawn in sharing the fate of his father and grandfather. One advantage of this curse is that it gives Miroku a deadly weapon which puts him on level ground with hordes of youkai, as there are many enemies throughout the series that can't be destroyed by any of his friends and thus he must use his Wind Tunnel to suck them in.
There are two main weaknesses of this attack; if he absorbs something with demonic poison (such as Naraku's insects known as the Saimyosho, or cursed zombies, or anything with a tainted aura such as the water from the god Numawatari) the poison will be spread to Miroku. Because of his holy powers Miroku has a strong resistance to demonic poisons but too much of it can kill him. The other weakness is that if some sharp object such as a knife is sucked into the hole and manages to pierce a side of the hole, then this injury must be repaired otherwise the hole will begin to grow at a much faster rate and thus eventually kill him sooner than his time. Such as in episode 28 when Miroku sucks in the giant mantis. Another good example is when, in InuYasha The Movie: Affections Touching Across Time, Hyoga's underling Ruri uses her spear to expand her own copied version of the Wind Tunnel and is consequently sucked into it, killing herself.
During chapter 448 of the manga, Miroku attempted to use the Kazaana on the merged Naraku and Moryomaru, but absorbed the Fuyoheki in their place, thus allowing Naraku/Moryomaru's youki to be detected once more. However, he also absorbed a large amount of shouki (miasma); though he was purified by Kikyo, the shouki had cut wounds deep into his body. Now, continued use of the Kazaana will increase these wounds as well, until they reach his heart and kill him.
As of Chapter 536, the Wind Tunnel has reached its limit, opening it one more time will mean Miroku's demise. However, as of Chapter 548, when Naraku has been hit by InuYasha's reformed Meidou Zangetsuha, the Kazaana ceases to make noise, meaning that it has been calmed down, and by Chapter 549, as stated by Miroku, it has begun to close. In Chapter 553, right after Naraku's death, Miroku takes off his glove and sees that the Wind Tunnel has definitely disappeared.
Holy Powers:
Super Speed: In short bursts, Miroku can run swiftly enough to keep pace with InuYasha; even if carrying extra weight (i.e., another person) on his back. Whether this speed is granted by spell, innate ability, or even extensive physical training is unclear.
Spell Scrolls: Can be used to paralyze youkai and create barriers. Most are thrown and then bind to the youkai, often for disarming purposes. Miroku usually employs these as an alternative for the Wind Tunnel, especially when it happens to be unavailable at the moment.
Invisibility: Miroku can mask objects (both living and inanimate) from the eyes of evildoers, by going into a state of intense meditation.
Barrier (Kekkai): With the assistance of his staff, Miroku can create and temporarily sustain small protective force fields of reasonable strength.
Holy Staff: Miroku's staff, known as a Shakujo, is a metal staff with a circular golden charm on the top. The charm is a circle with a pattern through the center of spheres and double crescents. On each side of the circle, there are three thin gold rings. It is effective in destroying youkai due to its holy properties, though it strangely acts like a spear or an axe, cutting any demon it comes in contact with. His grandfather, Miyatsu, originally wielded it when he fought Naraku. This staff was able to stand up to the original Tetsusaiga, indicating that it is a very powerful weapon on a similar level to the basic levels of the sword. This is most likely because his grandfather, who was very powerful, endowed it with his spiritual powers, or perhaps even forged it.
Fury of Taishaku: Miroku uses a weapon to summon down some lightning bolts down at his foes. He only uses this attack in InuYasha: Secret of the Divine Jewel.
