Kylo Ren, a human male, was a Force warrior and former Jedi Padawan under Jedi Master Luke Skywalker, before Ren formed the Knights of Ren and joined the First Order. He was born a year after the Battle of Endor.
Kylo Ren grew up on Tatooine. As a child, he knew Lor San Tekka. When Kylo was 9 years old, he was found by Han Solo.
Kylo proved to be force-sensitive. He began training with Luke Skywalker as one of the students that his master was training in the hopes of restoring the Jedi Order.
Fall to the Dark Side
Kylo ultimately betrayed Skywalker and embraced the Dark Side of the Force. He assembled a group of like minded Padawans and formed the Knights of Ren to destroy everything Skywalker tried to build, leaving his Jedi temple in ashes and killing Luke's wife Mara Jade Skywalker and the rest of Luke's students.
With his Jedi destroyed, Skywalker went into exile. Ren joined the First Order. His actions as a Jedi earned him him the nickname "Jedi Killer".
Though he had direct access to the Supreme Leader and could command military officers, he existed outside the official command structure. He never got along with General Hux, seeing him as a failed soldier of the Empire.
Raid on Tatooine
Both Ren and the Supreme Leader understood that if Skywalker or the Jedi returned, they would be a threat to the First Order. The First Order learned Skywalker had gone in search of the first Jedi temple which had been lost and the map was in the possession of Lor San Tekka, a member of the Church of the Force on Tatooine, who believed the return of the Jedi was essential to bringing balance to the Force. Ren and Phasma led an attack on Tatooine.
Once Phasma rounded by the denizens of Tekka's village, Ren confronted Tekka, demanding the map. Tekka refused and Ren killed him. Moments later, he was shot at from afar by Poe Dameron who was sent by General Organa to find the map before the First Order. Ren used the Force to the stop the blaster bolt mid air and Dameron was soon brought before him. The darks warrior realised Tekka gave the map to Dameron and ordered the troopers rob ring the pilot onto Ren's command shuttle, before giving the order to kill the rest of the villagers.
Unknown to Ren at the time, Dameron had hidden the map inside his droid BB-8, shoe escaped as the First Order attack began. Ren used the Force to mentally extract the information from Dameron's mind. The pilot was forced to reveal he hid the map inside his BB unit and that the droid was likely still on Tatooine. Ren informed Hux of the new development and left the recovery of the droid in the hands of the military.
The First Order soon learned that Solo, Rey, Finn, Dameron and BB-8 had landed on Takodana and were in the castle of the ancient pirate Maz Kanata, who Solo hoped would deliver the droid to the New Republic.
Ren led his forces to Takodana, where Stormtroopers attack Kanata's castle. Solo, Finn, Dameron and BB-8 were briefly captured by the First Order until New Republic X-Wing fighters arrived to recover the droid while Rey and BB-8 tried to escape through the forest. Ren soon arrived on the battlefield and found Rey in the woods. She fired at him with her blaster but he reflected her shots with his lightsaber. Finally, Ren froze her in place with a telekinetic attack. He attempted to interrogate her about BB-8's location by probing her mind with the Force, learning that she was Skywalker's daughter. Ren was forced to retreat when X-Wing fighters attacked him.
Han Solo's Last Stand
On the Finalizer, Solo confronted Ren and called to him, using his birth name. Ren told Solo that Skywalker did not do enough and impaled him with his lightsaber.
Enraged at the loss of his best friend, Chewbacca fired a powerful shot from his Wookie nowcaster but Ren caught it with the Force. He then pursued Finn and Rey as they made their way back to the Millennium Falcon.
Duel on Yavin IV
Ren followed Rey and Finn back to Yavin IV. He confronted them, lightsaber drawn. Rey tried to attack him with her blaster but he used the Force to throw her into the wall and knock her unconscious. Left alone to confront the dark warrior, Finn ignited the lightsaber that had been oven to him for safekeeping by Maz Kanata, a lightsaber that belonged to Luke Skywalker and to Anakin before him. Finn engaged him in a lightsaber duel. In the end, Finn was no match for Ren's power. Ren overwhelmed and disarmed the former stormtrooper, leaving him comatose.
Rey used the Force to call the lightsaber over. Rey ignited the weapon and engaged Ren in an intense duel. At first, Ren had the upper hand, remaining on the offensive as he pressed his attack against the retreating scavenger. Their blades became locked and Ren told Rey that he was the one who abandoned her on Tatooine after stealing her from Skywalker. He was attempting to train her as his own apprentice. Rey was able to briefly turn the tide of the fight and push her own offensive against the dark warrior but was soon disarmed when he chopped her hand off.
Before they could engage any further, the surface of the planet began to break apart, Star Killer Base had fired at Yavin IV. Ren and Rey were separated by a deep chasm, so Ren left Rey behind. Rey recovered Finn and left the planet with Chewbacca via the Millennium Falcon.
Kylo Ren was dissatisfied that Skywalker's Jedi Order and the New Republic had not been unable to help various planets, including Tatooine and grew impatient with the lack of change despite the fall of the Empire. Despite turning to the dark side, he still considers himself to be a Jedi. He despises the Empire and considers the First Order to be different. He studied both the skills of the Jedi and the Sith.
Powers and Abilities
Kylo Ren was tasked with destroying any remaining remnant of the Jedi, including his former master, Luke Skywalker, whose attempt to restore the Jedi Order was thwarted when Ren betrayed him. Ren's abilities gave him powerful abilities with the Force and in combat. The dark side that flowed through him made him a nearly unstoppable force and he was a powerful use rod telekinetic attacks and defences. He was capable of holding a blast bolt in mid air for several seconds and he could telepathally invade the minds of his prisoners and psychologically torture them into revealing withheld information.
Ren, who pulled his teachings from both the light and the dark to hone his power, was skilled in lightsaber combat.