SO I wrote this after the S4 finale so I know a lot of this is wrong. Like Thea leaving to find herself. But oh well, let's say she did it for a month before S5 starts. Besides that, hope you enjoy.

Oliver paced impatiently across the loft. It was been the day after Darhk's death and it turned to night.

The loft was deafening darkness that reminded him of the island. The
light only came from the moon through the window.
He looked around the empire place.
Almost all of her stuff had disappeared from the apartment and the
fact hit him harder.
She really is going to leave.
His head snapped to the doorway as he heard a creak.
"Wrong way" A voice whispered behind him.
He turned around as he saw Thea in her Speedy costume, crawling in
from the window.
"Thea.." Before Oliver could get out any preliminaries or the "How are
you feeling" speech he planned after he texted her to meet him.
Thea went for the kill.
"What do you want." Thea demanded. Though he couldn't see her face,
her voice said it all. Hard and defiant, daring him to challenge her,
to question whether she was as much as a monster she felt. But under
it, he sensed a tiredness. It'd been a long night and she was trying
to keep up the hard edge in her voice.
"I want to talk to you"
"You are not talking me out of this. I THREATENED A CHILD! Sure, she
was Dahrk's kid but still! And worse, I wanted it. I wanted to kill
again. It feels like it would be so much easier to get rid of any
witnesses or distractions or obstacles. I killed one person, then I
killed another and now I can't stop. I hate that. I wanted to defend
myself and help and now I'm just messing everything up. I'm turning
into Malcom" Thea muttered as she slumped to the floor after her rant.
Oliver felt his heart drop to his stomach. He flash-backed to 7 years
ago when he last saw her as a little girl, running around the mansion.
She always been so happy and now... She seen more death and lies in
her family in 2 years than all the ones he had disappeared in the
island.
"You're not like Malcolm at all." Oliver walked over and sat next to her.
"It's just the side effects from the pit. I'm sorry you had to go
through this. I didn't think it would hit you this bad...I love you
too much to let you get killed by Ra for me of all reasons and I just
wanted..."
"Ollie, please. Enough about you and your guilt." Thea snapped
"My guilt...No, I" Oliver protested

Thea gave him a look, "Oh please, you always feel guilty. About Sara,
and Dad and Felicity and the whole city and.."
"Felicity., I only..I mean" Oliver stammered
"And know what, let me clear this up for you. This one, this is not
your fault. Yes, Ra went after me to get to you and you revived me.
But know what? Sometimes other people are out fault. Some things are
out of your hands. People react and make their OWN decisions and do
stuff. Maybe you started it, but the rest people choose to do
themselves. So this is my choice. Other stuff was my choice. And some
of them been bad but that's my own guilt. None of yours. So you can't
talk me out of this because you feel it's your fault because.."
"I don't want you to die!" Oliver blurted out interrupting her rant.
The light of the moon splashed across her face at the moment, and he
saw the confusion and slight anger at his interruption.
"I can take care of myself, thank you very much."
"No," Oliver sighed. He forgot how hard it was to be so open, so
vulnerable but he plunged ahead.
"I mean like last time. When you refused to kill and the bloodlust
started killing you. You're my only sister. You were one of the things
that kept me going, that I'd come home and see you and start one of
our stupid fights. And I was glad to have you help me with Team Arrow
but I'm not going to make you stay. know I can't stop you and I won't,
I know how it feels to be a monster going down to the dark side but
that night when you were dying. I understood it was your choice, but
still. All I could think about was that my little sister was going to
die. And I didn't know how much I needed you. I got how you felt when
I was at the Island. I wanted you to be here with me. I wanted you to
be right next to me to mock all the overdressed clients and my
sparring partner and archery rival and general pain in the ass. And I
missed all the memories we had back when we were younger, Speedy. I
realized, I needed you as much as you needed me.
So please, if you're close to... the first time you faint, tell me."
"I didn't know you felt that way." Thea whispered "I still do need
you. You're the only family I have left."
Thea turned to him and hugged him with so much force, he tumbled to
his back. Oliver let out a small smile. It was so spontaneous and
child-like. It reminded him of her 7th birthday when he brought to
her, his and Tommy's "secret" hang out and they played "The Princess
and the loser robber" until dark. He had been the loser robber that
got beat up at the end of the game, multiple times. She had hugged him
the same way when he told her.

"And I'm not going to die. You wouldn't let me." She continued,
rolling off him so she could lie on the floor and stare at the ceiling
next to him.
"Of course, I will visit you, dying or not. Especially if you're ass
is getting kicked too much without me"
"That does NOT happen" Oliver retorted
"Fine, if you're being an idiot with Felicity" Thea said
"What's between us is our..." Oliver trailed off as a new thought came
to him. "So...how are you going to recuperate? You said you'd hang
out, find people and stuff...Is Roy one of those "people" and stuff"
"How did you? I mean no! I am going to be doing stuff! I don't know
right now. I mean.." Thea stammered
"What are you two doing?" Oliver questioned
"I am not discussing that with you."
"Excuse me! I swear, if he tries to pull some sort of.."
"Oliver, don't push it or I will tell you exactly what positions we
are going to do" Thea hissed
"Dude! Ugh! No, that's wrong" Oliver groaned as he tried to bury the
image Thea was implying.
It soon lapsed into another silence only broken by the sound of a bird
chirping.
"I should go." Thea got up but made no move to leave until Oliver stood up.
"I'll miss you" Thea lightly punched his arm.
"Miss you too. Don't die" Oliver replied, the meaning sounded entirely
different after their talk than just a casual safety reminder.
Thea put one leg out the window until Oliver said..
"You know the door is completely usable and actually quite helpful if
you want to leave an apartment."
Thea rolled her eyes "Well that takes away from my cool exit." But she
walked out and turned with a small smile, "Bye"
Oliver gave a reassuring smile back, "Bye"