This is my take on the Blake siblings fight as shown on the Season 3 trailer.
English is not my first language, so please excuse any grammar mistakes :)
For the first time in five days, Octavia Blake looked at her brother. He walked slowly on her direction, stopping right in front of her. She could see Indra's retreating form as she cleared the area for the talk the siblings were about to have.
The first thing she noticed was that the guard jacket was gone but that did not help diminishing her anger. It was a little too late now. Other than that, Bellamy did not look good.
If she was being honest, he looked older than his actual age, his eyes swollen and filled with unwashed tears, his hair dull and lifeless, his face wrinkled and pale. He looked like a broken man, his shoulders hunched in a clear sign of defeat. Like he was about to fall apart right there in front of her.
Octavia had never seen her brother devastated like this but she was unable to feel pity for him anymore. Actually, she was unable to feel anything. She was consumed by an endless numbness, like she was swimming alone and naked on a frozen lake. She could feel the dark and cold water all around her, desensitizing her skin and filling her up with emptiness.
"I-I am so s-sorry". He stuttered, his voice hoarse and filled with sorrow. His apology seemed genuine but it only served to drive away her numbness and refill it with pure anger.
She involuntarily balled her wrists and clenched her teeth. She had never felt such anger before, not even when the ark guards had floated her mother and arrested her for being born. Back then, her anger was directed at the ark people but now it was directed to her own brother - her own blood. And his betrayal made the anger 100x worst. He had sided with Pike, he had murdered the grounder army, he had broken the coalition and he was directly responsible for Lincoln's death – her lover's death.
Lincoln was the only man that ever saw her as his equal. He understood her need to be herself and never judge her like all of the others. If she wanted to be a grounder, he helped her. He trained her, taught her the basics of fighting. He taught her the trikru traditions and language. He supported her training with Indra. He was proud of her accomplishments. He showed her how to love unconditionally and to be kind. He was her partner, her soulmate, her friend. And now he was dead, gone. Cruelly ripped from this world while he was trying to make it a better place.
The image of Pike shooting Lincoln in the chest in front of Arkadia immersed itself on her thoughts. There was so much blood. Lincoln fell first at his knees. He looked around with a stunned expression searching for her, but he succumbed to the ground with a loud thud before their eyes could cross.
She fought hard to get rid of Bellamy's grasp and run to him. She kicked, screamed, cried but her brothers arms were like an iron grip around her. He only stopped holding her back when she collapsed on the ground and vomited at his side.
Now he was here, apologizing like it could save their relationship. No, an apology would not bring Lincoln back. She could feel herself trembling slightly and from Bellamy's expression he could also read her movements and knew what was about to happen.
He did not even deflected when her knuckles contacted hard with his face. His head was thrown to the side and blood immediately started cascading from his nose. Octavia could feel tears falling from her eyes as she realized that this was their turning point.
She hit him one more time, furthering their connection as siblings. He stood in place taking it, as if he knew he deserved it.
"You are dead to me!". She shouted as she landed the fourth and last punch, her knuckles swollen and bruised. As she retreated her arm, she felt as if she was cutting the invisible umbilical cord that used to link the siblings. There was no turning back now.
He lifted his head on her direction and she could see the tears falling down his face mixing with the blood. She knew her words had cut deep inside him, more than the physical violence. From the beginning, it was Bellamy and Octavia versus the world. The Blake siblings. The brother and sister that fought against everything and everyone to keep each other safe. Now there was just Bellamy, a mass of blood and regret on the ground, and Octavia, a grieving woman alone in the world.
Their eyes met, his asking for forgiveness and hers filled with despair and anger. No, Bellamy, she could not forgive him for such unforgivable act. As they looked at each other, her anger dissipated and the cold numbness took over once more. She sighted with relief as she was not able to feel anything anymore. It was easier this way.
"If I see you again I'll kill you. I swear". And with that she left the tent, cutting on that moment all the ties she had with the arc people and her dark past. Gone was the girl who used to hide on the floor when the guards came. Gone was the reckless girl that set the first feet on the ground when the dropship landed with the 100 teenagers. She was a woman now, a grounder woman.
"Look at yourself. It is time to stop playing grounder before you get yourself hurt". Bellamy had told her a few days before. He simply did not get it. She finally found a place where she was accepted. She finally belonged somewhere. And now, for the first time, she was 100% grounder, nothing to hold her back.
She got out and marched towards Indra, her blank expression back in place. The older woman uncharacteristically put a supporting hand on Octavia's shoulder. After a few seconds, she wordlessly grabbed Octavia's hand and bandaged it with a clean cloth. The girl nodded her appreciation at the kind gesture and they started walking to the commander's tent. They had a mission to accomplish. Arkadia would pay for the massacre and Pike had a personal debt to her. Blood must have blood, that was the grounders way.