Appearance and Abilities
Often described as a "pretty youth", Narishma is quite young with dark eyes, a pale face, and long dark braids with silver bells at the ends. Narishma was born with the innate spark, but it hadn't yet manifested before he was discovered by Mazrim Taim. Though his absolute strength in the One Power is unknown, he appears to be astonishingly powerful, even among men. Rand al'Thor describes him as "just behind Logain, who was just behind himself." This indicates a upper bound of strength on the Power Strength Scale as being ++3; or possibly one of the most powerful Channelers in the world.
Dumai's Wells and the Seanchan
Narishma is one of the Asha'man who were part of Rand's rescue in the Battle of Dumai's Wells. In the aftermath of the battle he is one of four Soldiers chosen to accompany Rand. He stands guard over Rand when he is meeting with some of the Aiel clan chiefs and when Cadsuane Melaidhrin arrives and insults Rand. Rand says that he, along with Eben Hopwil and Damer Flinn, are the only Asha'man he can trust.
He is one of Rand's bodyguards when he meets with the Sea Folk and makes the Bargain. He Travels to Illian with Rand in order to confuse Sammael and try to bring him back to the city of Illian so Rand can finally defeat him.
He is with Rand when Rand meets with the rebels loyal to Lord Brend. Rand promotes him to Dedicated. Rand then sends him to Tear to retrieve Callandor from the Stone of Tear. He retrieved Callandor from the Stone for Rand, so he has some further purpose in the series, according to the Prophecies of the Dragon. The alternative is that Jahar shall follow Rand loyally.
"Into the heart he thrusts his sword, into the heart, to hold their hearts. Who draws it out shall follow after. What hand can grasp that fearful blade?"
He is angry at Rand for forgetting to tell him about some of the inverted weaves he left behind, which Rand denies. He then rides with Rand when Rand's forces attack the invading Seanchan just outside Illian. On arrival back to Cairhien, Rand charges Narishma to guard Min Farshaw when he goes to his meeting with Cadsuane. When the rogue Asha'man attack Rand's quarters, Rand nearly fries Narishma on purpose due to his lack of trust of the Asha'man.
Cleansing of saidin
Jahar Travels with Cadsuane and Merise to Far Madding to track down Rand. While there he is sent to the outskirts of the city limit and to channel. He then goes with Cadsuane to meet with the Counsels of Far Madding when they have Rand prisoner. He pretends to channel saidin in order to break Aleis Barsalla and set Rand free.
Linked to Merise and wielding Callandor, he participates in the Battle near Shadar Logoth.
He accompanies Rand and Merise to Algarin Pendaloan's house in Tear, where Rand recovers after cleansing saidin. He practices swordplay in the courtyard with the other Warders. He keeps challenging Lan Mandragoran in a duel and continues to be defeated by him. Narishma was promoted to full Asha'man after the cleansing, though Merise refuses to allow him to wear the Dragon pin for reasons of her own.
Rand sends Narishma and Merise - along with her two other Warders, Bassane and Nethan - to the Salidar Aes Sedai camp. Once there, he speaks before their Hall and informs them that they may bond forty-seven Asha'man in order to match the number of Aes Sedai bonded by Asha'man at the Black Tower. While there he detects someone channeling saidin and warns them of one of the female Forsaken who can channel saidin.
He is one of the six to accompany Rand to his meeting with the Daughter of the Nine Moons. A fight soon breaks out when the Daughter of the Nine Moons is actually revealed to be Semirhage in disguise. He is Healed by Merise after the fight.
He accompanies Rand to Lord Tellaen's manor in Arad Doman. He is present while Merise interrogates Semirhage. Rand then uses him to transport Rodel Ituralde and his troops to the Blight near Saldaea. He escorts Merise to Rand's room after Semirhage's escape. Rand teaches him how to use balefire to destroy the Forsaken. Narishma then transports Dobraine and his men to Tear. He goes with Rand to Falme, where he meets with the real Daughter of the Nine Moons, Tuon Athaem Kore Paendrag.
He rides with Rand when Rand goes to meet the Borderlander rulers inside Far Madding. On return to Tear, Rand sends Narishma back to the Borderlander army to say that Rand accepts their terms and that he wishes to meet with them.
Nynaeve Heals the damage caused when channeling while saidin was still tainted, ridding Narishma of any trace of madness. He accompanies Rand again when he re-meets with the Borderlander rulers in Far Madding. 
The Last Battle
Narishma is one of Rand's escorts at the signing of the Dragon's Peace. When Roedran Almaric do Arreloa a'Naloy enters the pavilion, he stands at attention just in case Roedran was Demandred. Narishma fights with Merise in the Borderlander battle front at the beginning of Tarmon Gai'don. He transported Bulen's body to a frozen place where it could be preserved long enough for it to be buried in Malkier at the end of the Last Battle. He and Merise were told to watch out for Dreadlords and kill them.
At the battle of the Field of Merrilor, the Asha'man and his Aes Sedai stood beside the Amyrlin Seat, where Narishma could identify weaves of saidin for Egwene to cut down. He directed Egwene during her first confrontation with M'Hael.
It is presumed he survived the battle.