Welcome to Backstory part 2/3. Let's jump right in shall we?
This has Abe's Official Seal of Approval.- Here by request of the person who owns Abe's character

Abraham Marcus Lyall came from a poor family, no, poor was an understatement. His family was destitute. His father died of a drug overdose when Abe was 9, though by that time he was quickly becoming a master thief.
And then he found parkour.
Oh dear sweet lord on high parkour.
Within minutes of finding the sport Abe was obsessed, working out ways to throw himself up walls, jump from roof to roof, anything acrobatic and flagrantly dangerous.
Whenever he wasn't working his way through homework (which felt amazingly unimportant) or stealthily borrowing food and other necessities from the local stores to keep his mother and sister from dying of malnutrition, he was practicing. He was constantly covered in scrapes and bruises, he learned to disguise a sprained ankle with shocking proficiency, once he even broke his shoulder falling off a roof when he didn't quite make the leap. The pain didn't matter so long as he got that exhilarating thrill.
Around twelve he managed to steal a box set of an anime, and seeing the ninjas set him right on the track to finding a new use for his hobby.
Carefully altering parquor to be silent and hidden, he started using his capabilities for thievery and his hauls tripled. He managed to perfect the art by 14.
His fortune just wasn't meant to be, within two years of the breakthrough that had his family fed the zoms came.
"Nat, close the door!"
"But mom!"
"Nat I said close the door!"
Abe didn't have the heart to tell his little sister that he'd shot their mother several miles back as they fled the slums they called home, especially not when she was staring at him with those tear filled blue eyes. She threw the door closed and moved out of the way while he started everything he could in front to barricade it while she watched in utter terror.
Satisfied nothing would get through he took her by the wrist and dragged her up the stairs of the abandoned building, hoping to find a door to the roof.
"Abe I'm scarred!" She was crying full on now, sobbing even.
"I know, I know." He couldn't stop moving, he had to get them out of the city, or at the very least to the edge so he could get them out when the sun came up in the morning. "There's not much I can do about that."
"I want to stop and wait for mom!"
"We can't!" The building was five stories tall, they'd gone up two.
She halted, and he very nearly pulled her over, "I want to wait on mom!"
He could hear the zombies against the door below.
"We can't stop Nat. She'll find us. Right now we need to worry about not letting them catch us." He kneeled down in front of her, straightening her yellow-blonde hair. "I know you're scared but I need you to be brave for me okay? Just keep running."
She was biting on her cheek.
"Natalia, please." He wiped a few tears from her eyes, "We need to go."
She was only 8 years old. This was way too much for her.
Nat sniffled and nodded, "O-Okay."
Relief swept over Abe, "Good." He stood and took her hand, "Let's go."
They were on the fourth floor when he heard the door give and his barricade start screeching across the floor.
"Abe-"Natalia started nervously. He started throwing open doors.
Wrong.
Wrong.
Wrong.
Finally he came across the door leading to the stairs, "Up we go."
He shoved his little sister in toward the stairs and slammed the door behind them, "Go!"
The little blonde obeyed without question, panting as she approached and threw open the door to the roof.
She stopped when she reached the open air, taking a deep breath.
Abe hauled her onto his back in one smooth motion that had him rather impressed with himself and kept running, making a leap for the next roof.
Somehow running parkour with a heavy backpack was turning out to be very helpful in the apocalypse.
Who knew?
Natalie screamed when they hit the next roof, but Abe just grit his teeth and kept going.
The sun was going down, it would be difficult to keep going once it really started to get dark.
And his sister wasn't helping him focus at all.
After a few more roofs he finally decided to stop as the sun sank down behind the skyline. He let his little sister off of his back and checked at the door to the roof, finding it blessedly locked and dang near impossible to open.
"We're going to sleep here."
Natalie stared at him incredulously, "What?"
"Here. We sleep on the roof."
She nodded slowly, "Alright."
The boy shrugged off his thin cotton jacket and handed it over to her, "Go make yourself comfortable."
He plopped down onto the ground in front of the door, closing his eyes and letting his body relax.
"Abe?"
"Hm?"
"I'm scared." Natalie came and sat beside him.
He put an arm around her, "I know."

People were rioting in the streets, attracting zombies from miles away. He stared down into the crowd watching the police attempt to fight off a quickly changing horde of rioters trying to escape the city.
"Do you think they'll be letting up any time soon?" Natalie asked, peeking over the edge to the violence below, "I'm hungry."
Abe looked over to her, "Well considering they've been here since this morning and are still going strong? I'm gonna say no."
She sighed, "Can't you just start running over the rooftops then?"
"We're safe up here and if I fall we're dead."
"What about going down?"
"We can't get the door open."
She groaned and flopped onto the smooth cement, "I'm so bored!"
"So am I." He had to admit, at first there'd been a factor of morbid entertainment to watching the crowd but after about half an hour that had faded.
She lay down next to him.
"You want to play twenty questions?"
"Sure. Why not."

By noon on the second day, Abe's patience was long since passed, "You stay up here, I'm going down."
"But-"
"We need food, or at the very least water." Abe looked down into the writhing crowd of police and civilians, a weapon wouldn't be bad either. "You stay here."
"Abe!" She was tearing up. Poor little Natalia had been doing so well about not crying to.
He grinned, faking confidence to keep his little sister calm, "Chill out Nat, I'll be back."
He started dropping himself down the wall into the horde, there wasn't any point to trying to avoid it; the things were everywhere.
He could see Natalia watching him over the edge until he threw himself into the mass, surviving only on virtue of his honed agility until he managed to rip a riot shield off of some poor, recently turned riot officer's shield. That in hand he could manage to fend off the zombies.
He found himself thrown to the ground, but he was lucky enough to keep the zombie on his shield until groping on the ground landed him a heavy black stick to attack it with.
The combination of weapons and agility gave him the chance to fight his way through the crowd and start hunting for somewhere to get food.

"Hey there kid where you at?"
"A place."
"Look we can't help you unless we know where you are."
"Don't need your help."
"Is there anyone with you that might need help?"
Natalia came to mind.
"Do you mind if I go and find the address where they're at?"
"Just call back okay hon?"

Abe had always been close with his sister; asides from their mostly despondent mother she was the only family he had left.
Most siblings fought a lot, but not Abe and Natalia, sure they had the occasional row but for the most part they got along swimmingly. He spoiled her with stolen sweets and dolls and she always reacted with excitement, even when their mother reprimanded him for his antics she was happy to see him.
He was her protector, her guardian, and that was something he took great pride in. He was going to get her through collage and everything. Give her a real shot at life.
That was his job as her big brother, look after her and get her where she needed to be.
His optimism was renewed now that there was a real shot at helping her. He raced back to the building he found her in, fighting his way up a few buildings over parkouring his way over in a rush of excitement.
The roof was empty. The door was open

Abe searched rooftops well into the night, but he had no luck. He searched rooftops for days, nothing.
Natalia was gone.
He'd failed.
The scrawny teenager was suddenly alone, hit by the full brunt of everything that had happened.
He shot his mother.
His little sister was gone.
She was probably dead.
The apocalypse was in full swing.
Abe sat down on the roof of a building, looking down into the park.
"Hey."
"Hey there, did you find them."
"No."
"Oh… Do you still want to stay there?"
"No."
"So where are you?"
"I'm near Klyde Warren Park."
"In Dallas?"
"Yeah."
"That's… That's quite a ways away from where I am."
"So I'm on my own?"
"No, no we can get you it may just take a while."
"I can wait."
"We'll be there as soon as we can. Can you stay where you are?"
"Yeah."
"Do that."
"Okay."

He didn't like to deal with the other kids. Really he didn't like to deal with anyone. He skipped his classes. He snacked all the time since food was relatively available. He really just wanted to be alone.
He was sitting on a ledge when a pair of girls passed under.
Neither of them were very big but the smaller of the two was brandishing a thick copy of a book with a rabbit on the front and excitedly chattering to her companion in a flurry of words so complicated it sounded like she was speaking another language.
The other girl, a tiny thing with auburn hair was nodding along, though the wire hanging from her ear suggested she wasn't listening. Not to the blonde at least.
Though her wicked grin suggested she was every ounce as excited for the mischief they'd be getting into.
He recognized the auburn haired girl, she frequently skipped class and hung around the halls listening to music and drawing. The other one was unfamiliar though, which was surprising considering that the distinctive blue streaks in her hair should have set her apart from the crowd.
Curiosity led him to jump down and follow the girls out of the building and to the courtyard, watching curiously as the girls gathered wood, organized their kindling and eventually built up a rather impressive fire.
The auburn haired girl was grinning maniacally as they started ripping pages from the book and throwing them into the fire.
"What the heck are you doing?" Abe's own voice surprised him, he hadn't really initiated conversation since the call to the local communications office that had gotten him picked up.
The red haired girl glanced to the blaze, "What does it look like we're doing? We're making a fire."
"You're tearing up a book."
"We're tearing up a pretentious, poorly made excuse for a piece of literature." The little blonde ripped another page from the book and cast it to the flames. "Might I inquire as to what you're doing?"
"Investigating."
The girls looked to each other and then shrugged.
"Want to burn shit with us?" The auburn haired girl asked.
He shrugged, "I guess."
She whipped out a cigarette, "I'm Salem, that's Ema."
"We're calling her Pyra now." Ema was grinning into the flames as the pages smoldered. "You're that kid from Dallas right?"
"Yeah."
"The one that had to fight through a riot?"
"Yeah."
"Well Pyra it seems we've got ourselves a Rioter."
Salem laughed a little, "I suppose so."
"A rioter, a pyromaniac and a genius."
"We sound like the beginning of a bad joke."

He didn't like being alone. Well not really alone. What he missed was the girls. Without Ema and Salem he ended up focusing on his previous failures, worse he ended up thinking of how he'd failed them too.
They were furious with him.
And Salem was right he really couldn't deal with the other kids at the school, he ended up striking out on his own in frustration.
He could hear shots in the distance sometimes or surprised moans of zombies, he supposed that meant they were doing fine.
Natalia started nagging at him again. He'd managed to push her to the back of her mind when he could focus on SE and Pyra and the school. All alone she never stopped worming her way into his mind.
He really shouldn't have fought with Pyra.
He really should have listened to SE.
He really shouldn't have abandoned the school.
He had to get them back.
He wasn't ready to think on Natalia yet, but he was ready to reunite with his friends.
A shot fired in the distance.
On the bright side, he knew where to start.