Don't mess with the devil

Intro- A war in his head.

A war. This is what is going on inside his head. He can't sleep after hearing namjoon's words. He can't believe it, did it really happened? He can save himself and his sister, but on the other hand... it's his father...
Taehyung hates this word- "father".
It is because he never actually had one. Mentally at least. His mother disappeared when he was 6 years old, no one knows why but Taehyung is sure it's his father's fault.
You see, his father is an alcoholic since he was in his 20's. Instead of giving his kids warm meals, love or even clothes- he comes home late, drunk and only traumatize them.
His name is Leon, Leon Taehyung.
Yes, you guessed it right, the same one who was sitting in jail for 17 years. You know who I am talking about...
Taehyung couldn't suffer anymore, he cared more about his sister than for himself. He called namjoon, asking for help.
He got an answer he didn't expect for, but at the same time, he didn't reject it.
What Taehyung didn't know is who he is really talking to.

•"Namjoon you've got to help me! I can't take this anymore! This guy- this guy is hurting Jennie again"
    * "This guy...? You mean your father?"
•"... yes" [sigh]
•"I just- I WOULD KILL HIM IF I COULD!"
    * "So do it."
Taehyung was surprised, namjoon sounded very cold with no expression. Taehyung didn't know wether he was serious or he was joking.
•"Wha- what do you mean?"
    * "You said you want to kill him, so do it. This jerk was treating you like shit for your whole life, and let's not even talk about your sister."
•"I- I don't know namjoon, are you serious?"
    * "I mean, I'll help..."
•"I'm-"
Silence-

No one hang the phone but no one talked. The tension was unbearable. If all you could hear is silence, why Taehyung felt like he is in a room full with people? He felt like he is being pulled under water.
Right before Taehyung hang up he heard;
    * "Ok Taehyung I'm very busy I can't let you keep waisting my time like this everyday."
•"Namjoon,"  Taehyung said quietly.
He inhaled deeply and whispered:
•"What if... what if I'll do it-"
•"how...?"
Namjoon's voice got deeper and louder and he immediately said:
* "Don't worry about that. Now, I need to go"
The call was finished.
Taehyung had many thoughts in his mind. He looked at his father, thinking he can't kill him-
Why? How? What if he'll get caught?
But then he looked down and saw his sister-
   The most important female for him. The only one.    Protecting him, taking the blame for things that he has done, giving him the last pieces of food
              -shaking on the floor. Her left eye is bruised from the morning. The eye was red and the skin around was purple, still very swollen.
Taehyung couldn't sleep for days. He is fighting with himself inside his head, he is trapped.
/a week passed from the last call\

[phone vibrating]
*bzz bzz*
*1 new message: Kim namjoon*