"Show me again… The power of the darkness… and I will let nothing stand in our way."
Kylo Ren was born with the name Ben and is the son of Hal Solo and Leia Organa. Little has currently been revealed about his childhood but he was found to be Force sensitive at a young age and was sent to his uncle Luke Skywalker for training as a Jedi apprentice. He holds some obvious bitterness toward his parents, particularly his father, so it is likely they did not know how to handle him and his budding powers and Han may have been more absent than not - or just not understood his sensitivities. Leia sent him away (to Luke) and from all of this he appears to have feelings of resentment and issues of abandonment.
He spent some undisclosed amount of time training with Luke alongside some others. It is said that one went wrong and "destroyed everything" and it is implied that this was Kylo, although a name isn't confirmed. He then became Master of the Knights of Ren, under the so-called Supreme Leader Snoke. He also changed his name to Kylo Ren, abandoning his former life, along with his birth name. Or so he wanted to, but even as he feels the pull of the Dark Side and moves along that path, he is also being pulled back toward the Light, much to his discomfort.
Joining the First Order, a group picking up the pieces of the fallen Empire, Ren became a formidable figure. With a look reminiscent of his grandfather and Sith Lord, Darth Vader - all in black and his face hidden by a dark mask - Ren exerted a lot of control over others, particularly in his use of the Force. He's struck up a sort of rivalry with General Hux and his presence is a constant challenge. They are often at odds, despite both following Snoke's orders. Sometimes Kylo's personal actions get in the way, as he lets that override what the Order wishes.
The mission to destroy the remaining Jedi resulted in the search for the last piece of a missing map, which would lead to Luke Skywalker. The Order had found the main part from the Empire's archives but one final piece remained elusive. Stormtroopers, along with Ren were sent to retrieve it from Jakku. Ren confronted an elderly acquaintance there, then killed him and ordered the rest of the village also killed. Back on base, he then mentally tortured the pilot Poe for more information, discovering it was with a droid - BB-8. Poe then escapes with a stormtrooper that Ren previously noticed was not killing the villagers - Finn. He would label him a traitor.
Later, finding out that BB-8 had escaped with the help of Finn and a girl - Rey - Ren flies into a fury, damaging equipment and almost choking the messenger. They finally track them down and Ren kidnaps Rey, leaving BB-8 behind as he thinks she has all the information that he needs. Trying to probe her thoughts with the Force, he is blocked as her own powers appear and strengthen. He is taken aback by this, especially when confronted with her words, that he is afraid he will never be as strong as Darth Vader. She has seen into his mind as well. Called to Snoke, he tells the Leader that she is strong with the Force but untrained. Snoke wants to see her in person but Rey has already escaped, using her budding Force powers. Again, Ren is enraged.
Finn, Chewbacca and Ren's father Han Solo then come to rescue Rey and destroy the First Order's Starkiller Base. Ren can sense his father near and there is a confrontation which results in Ren killing Han. He is conflicted even here, thinking this act will strengthen him by removing sentiment but it only weakens him further. Before he can process these emotions, he is hit by a blast from Chewbacca's weapon - one that quite often fatally wounds. But Ren recovers enough to go after Rey and Finn and a lightsaber battle ensues. First it seems that Ren has the upper hand, even if badly wounded, but he dispatches Finn, then Rey manages to focus her Force power and finds the strength to defeat Ren, but not to kill him. Ren is injured by multiple lightsaber blows to legs, shoulders and face and with the planet falling apart around them, Rey flees and Ren is left alone. Hux is called upon by Snoke to retrieve the fallen Knight and bring him back to complete his training.
As a character, Kylo Ren is always struggling emotionally and his personality is marked with instability. He is filled with an inner conflict that has yet to be resolved. This often shows in his face, which he often hid behind a special helmet, which masked his expressions. He can be quiet and watchful, observing others while he gains insight about them, whether through his instincts or more blatant use of the Force to invade their thoughts and minds. The latter is more of a last resort, if he wants information that they will not give up otherwise. When he wants something, he will rarely hesitate to take it but when faced with a barrier he can falter (such as when Rey fights mentally against his use of the Force to extract a map from her memories). This does not mean he gives up easily, however. He will continue to try, using all his skills.
While he sometimes can appear calm and in control, this is only when things are going well for him. His temper can blaze dangerously in an instant when something goes wrong, lending him an air of unpredictability that others may mock (behind his back) or fear. He's thought by others to be unstable or moody. A lot of this is due to the aforementioned inner conflict. He is sensitive to the Force, a sort of power and energy that is everywhere in the galaxy and around all living things. It can be used and manipulated by certain people and it runs strongly in his family, in both the so-called Light and Dark Sides. While Kylo wants to learn and gain more from the Dark Side he feels a constant pull to the Light. He thought this could be banished by acts such as removing sentimental temptations in the form of family; people who could lead him back down a path he doesn't want to take and people he potentially does still care about, despite his denials.
He can be very focused and self-centered. Working with the First Order, he often has his own agenda and will pursue that above the orders or needs of others. Even if when unmasked he can have an anxious gaze, there is can be an arrogance to his manner. He wants to think he's doing the right thing and that he is powerful enough to overcome any obstacle but he's not as strong as he wants to be - neither in will nor the Force. He knows he needs more training. This is not so say that he is weak. He has the stamina to push through a great deal of pain and he does try to push through emotional and mental barriers in order to get the results he wants. The turmoil and constant pulling from the Dark and the Light in his head, heart and mind do take their toll, however, making him less certain.
When his face is covered it enhances his confidence and he displays a more commanding presence and seemingly in control manner. It's something of an act, with the outfit masking not only his face but his insecurities as with it on he can be more like his grandfather, Darth Vader, in appearance - the one he aspires to emulate and finish the path Vader was on. Ren may have been misguided and has been influenced by Snoke, leading him down a darker path. It is a path he believes he wants to stay fast to and not stray.
Much as he tries, he isn't always in control of his own emotions and they can be very volatile. He can turn from seemingly calm to enraged at any moment and with little warning.
Kylo Ren has the Star Wars ability to use the Force. He has been trained in both the Light and Dark Sides and so has potential with both. These abilities include but are not limited to a sort of telekinesis: able to move, push and hold both people and objects; a sort of mind reading where he can probe into people's thoughts and see what they may be thinking or even see memories; he can sense others nearby presence with his sensitivity to the Force; he has enhanced skill with the weapon known as a lightsaber - and made his own so he has some technical skill there too. He also has a high pain threshold and can withstand damage that may kill others.
Grandson of Darth Vader.