Finrod Felagund
Finrod was the oldest child born to Finarfin and Eärwen. Through his grandmother Indis of the Vanyar, his mother, who was the daughter of Olwë, of the Teleri, and his granfather Finwë of the Ñoldor he was akin to all three races of the Eldar.
Finrod joined his friend Turgon in opposing Feänor and the oath. But once the armies of the Ñoldor were set to depart from Aman, they did not abandon their responsibilities. So it came that Finrod and his father Finarfin led the rear of the army that went in pursuit of Morgoth to Beleriand, seeking retribution for the murder of Finwë and for the theft of the Silmarils. But weary was the heart of Finrod: for he had to leave behind his beloved, Amarië of the Vanyar. For none of the Vanyar would leave Valinor.
After the kinslaying of Aqualondë and the prophecy of Mandos, Finarfin abandoned the journey and turned back with many of his people. Finarfin became head of the Ñoldor who remained there. But his sons and Galadriel did not go back with him, mainly for the sake of their close friendship to the sons of Fingolfin. Thus Finrod became king of the third house of the Ñoldor. Together with Fingolfin and his sons, Finrod led the host of the Ñoldor through the grinding ice of the Helcaraxë after the betrayal of Feänor.
In Beleriand, the high-kingship of the Ñoldor passed from the house of Feänor to the house of Fingolfin. But it was the destiny of the friends, Finrod and Turgon, to establish the great realms of the Ñoldor in exile: Nargothrond and Gondolin. In this they were led by Ulmo himself, who had laid a dream on them in which they were called to "prepare for a day of evil, and to establish a retreat".
When Finrod told Elwë Singollo of his admiration for the halls of Menegroth in Doriath, Elwë told him about the gorge of the river Narog. And it was there that Finrod delved the stronghold of Nargothrond. In this he was aided by the dwarves of the Blue Mountains, who were given many jewels of Valinor for their efforts. But the dwarves made for Finrod the necklace called Nauglamir, most renowned of all the dwarven-works of old. The dwarves called Finrod "felak-gundu", hewer of caves, and by the name of Felagund he was called since then.
The realm of Nargothrond stretched from Doriath and the river Sirion in the east to the havens of Cérdan in the west. In the north, Nargothrond even touched upon the very plains of Ard-Galen. There, in the narrow valley between Dorthonion ("Land of Pines") and the Shadowy Mountains, upon the isle of Tol Sirion, Finrod built the mighty watchtower of Minas Tirith. Thus it came that the realm of Finrod was the greatest by far in Beleriand, though he was the youngest of the Ñoldor Kings.
Wandering the wilds of Ossiriand, Finrod came upon the first of the Edain to cross the Blue Mountains, the kindred of Beör the Old. Then for them he played his harp and sang songs of learning and wisdom, and so he brought visions of Valinor to the first Men that entered Beleriand. And Finrod they called "Nóm", which means Wisdom in the language of these Edain. Finrod became a teacher to the Edain, and gave them lands to live in, pleading on their behalf before King Thingol. But Beör took service with Finrod and his family stayed in Nargothrond.
In the Dagor Bragollach, the armies of Morgoth led by Glaurung and many Balrogs broke the Siege of Angband. The sons of Finarfin bore the brunt of the assault, and Angrod and Aegnor were slain. But Finrod was saved from peril by Barahir, a descendant of Beör, and his men. For this Finrod swore an oath of abiding friendship to Barahir and his kin, and gave to Barahir his ring as a token.
Thus it was that many years later Beren, son of Barahir, came to Finrod with the burden laid upon him by Thingol: to go and take a Silmaril from the crown of Morgoth himself to gain the hand of Lúthien his daughter. And in this he sought the aid of King Finrod. Then Finrod knew himself to be ensnared in the Oath of Feänor after all. For in fulfilling his own oath to Barahir he would find the sons of Feänor on his path. And it came to be that many of his people were won over by Celegorm and Curufin, disclaiming an oath to a mere Man, claiming their first right of Oath and the Silmarils. Then Finrod and Beren journeyed into the valley between the Ered Wethrin and Dorthonion with only ten companions. But the watchtower of Tol Sirion was taken by Sauron, and it was renamed Tol-in-Gauroth. And Sauron was aware of everything that would pass. Thus befell the contest, a duel of song, between Sauron and Finrod which is renowned.
Sauron locked the twelve companions into a pit, and threatened to slay each of them cruelly, if they would not tell him the true identity of Finrod. But none would betray their lord, though each night a werewolf came to devour one of them. And when only Beren and Finrod were left, the werewolf came for Beren. Then Finrod in a last and desperate effort broke his chains and slew the wolf with his bare hands and teeth. But he himself was mortally wounded.
"He died then in the dark, in Tol-in-Gauroth, whose great tower he himself had built. Thus King Finrod Felagund, fairest and most beloved of the house of Finwë, redeemed his oath."
This biography was taken, with slight corrections and modifications, from the Valarguild website, until I have time to write my own.