Here is a write up on Nakul:
NAKULA
Nakula was the son of Pandu and Madri and was the fourth pandava.He was the twin of Sahadev.His father Pandu died early due to a curse and he even lost his mother who performed sati,hence it was Kunti his father's first wife who took care of him like her own son,infact she loved the twins more than her own sons(Yudhisthir,Bhim,Arjun).
Nakula was extremely devoted to his mother and elder brothers who looked after him like their life.He along with his brothers and the Kauravas got tutelage from Drona.Nakula was the most handsome man on earth and was along with Sahadeva the finest swordsman on the earth.He was equally well versed with the bow,mace and other weapons.He had a great talent to ride a horse while it was raining and not get affected by the rain.He was a master of unusual astras and a maharathi i.e great warrior.He also along with Bhim,Arjun and Sahadev captured Drupad and gave him to Drona as a revenge Drona had with Drupad.Nakula along with all of his brothers married Draupadi ironically Drupad's daughter.He also had a son by her named Satanik who would become a great warrior.Draupadi described Nakula as the most handsome man,best swordsman and a great car warrior.She also told that he was the most devoted brother and was bravest of all people.
When Yudhisthira lost at dice he wagered all his brothers,himself and Draupadi.Nakula was the first brother he wagered yet Nakula still did not utter a single word and remained calm and cool.
Before the dice game when Yudhisthira performed the Rajasuya yagna Nakula captured the whole of the western India for him.He defeated the Sibi ruler,he captured Malva,Saurastra,Keykayas and many other barbarian rulers.
During the exile Nakula was the person who collected all fruits and bought firesticks so that Draupadi could cook.He was the person who would fetch water whenever the others felt thirsty.He was the only brother who did not provoke Yudhisthira into war before the exile got over since he knew his brother would not fight before the exile.In the eighth year of exile he also saved Draupadi's life when they were climbing on a montain.During their climb Draupadi missed a step and fell down Nakula who was behind her caught her and held her tightly and saved her from falling.In the thirteenth year of exile -the year of disguise he used his talent of training horses to a great extent.He served in the stables of king Virat whereas his other brothers and Draupadi also took over other jobs in that kingdom.When the trigartas attacked Matsya kingdom of Virat he along with Bhim,Yudhisthir and Sahadev protected the kingdom from the invaders infact Nakula was the person who killed the great warriors of the Trigarta army.Earlier in the the twelveth year of exile when Jayadrat abducted Draupadi he along with his brothers cut down an whole army to rescue Draupadi.He used his sword to a great extent in that encounter.In the eleventh year when Duryodhan was captured by the gandharvas Yudhisthira ordered his brothers to rescue him.The four Pandavas defeated the gandharavs easily and Nakula again showed his valour by killing hordes of gandharvas with his celestial weapons.
KURUKSHETRA WAR
In the war against the Kauravas after the exile Nakula was the leader of one of the seven akshahuni the Pandavs had.Even though his role in the war was not as big as Bhim or Arjun he played a significant role in the battle.He along with Bhim led the Pandavas in the first day of the battle.He defeated Dushasan on the first day.He even checked the attacks of warriors like Bhishma,Drona,Karna,Duryodhan,Kritvarman and Ashwatthama.His most significant parts where in the killing of Bhishma when he along with few others breach Bhishma's inner ring which helps Arjun and Shikandhi bring Bhishma down.He also defeats his uncle Shalya in battle.He killed three of Karna's sons,Shakuni's son Uluka and also kills 180 other great Kshatriyas when he,Yudhisthira and Sahadev attach Bhishma on the ninth day of the war.His greatest battle he fights with is against Karna.He really fights valourously that day and even his unknown brother Karna is impressed.He breaks Karna's bow 4 times and wounds him very badly and that battle prolongs for an hour but Karna being a greater bowman has Nakula at his mercy in the end yet spares his life because of a promise he made to Kunti.Nakula was the one who killed all of Shakuni's men and was one of the survivor of that war.
AFTER WAR
After the war Nakula is appointed to look after the military of his brother Yudhisthira.He even gets the grandest palace of all brothers since he was the most regal looking.He even takes care of Dhritrastra and Gandhari like how he takes care of Kunti.After ruling the land for thirty six years he his wife and brothers die and reach heaven and get united once more.