Amanda Young was the sole survivor of the Jigsaw Killer's early killing spree, having survived the Reverse Bear Trap and come away with a new appreciation for life. Grateful to her kidnapper, Amanda quickly became Jigsaw's apprentice, working alongside him to test other people, including Eric Matthews, the detective who framed her.
When Jigsaw became sick with cancer, Amanda, growing cynical from the tests and Jigsaw's mentorship of Detective Mark Hoffman, became erratic, taking to self-harm and designing traps that were inescapable. Worried for his protege, Jigsaw decided to put her through another test to determine if she could be a worthy successor, requiring her to work with Dr. Lynn Denlon to keep Jigsaw alive while also overseeing the test of Jeff Denlon, who lost his daughter in a car accident. In part due to Hoffman's manipulation of her, Amanda's mental state gets the better of her and she shoots Lynn, killing her just as Jeff completes his test. Jeff, revealed to be Lynn's husband, shoots Amanda, who dies as Jigsaw explains her failure to her.
After her death, Amanda would wind up in the Entity's realm and sacrifice Survivors for the Entity as a Killer. Going by The Pig now, she would utilize an arsenal of various wrist-mounted weapons like the hidden blade and a drill, reverse bear traps, Jigsaw boxes, and Perks.
Battle vs. Dexter Morgan (by Pygmy Hippo 2)
Dexter Morgan groggily woke up and soon realized that something was wrong. He felt his head and touched metal. The last thing he had been doing was investigating the Jigsaw Killer case and like a certain detective had wound up in the game. He had fallen asleep in his bed but could tell this wasn't his home. He worried about his son before the television crackled to life, revealing a puppet.
"Hello Dexter, your son is fine. You think you're more than a common murderer just because you target other killers. You've caused the death of your wife and brother in your pursuit to satiate a Dark Passenger. But it will end tonight, life or death. Make your choice. The device on your head is called a reverse bear trap. It will tear open your head in two minutes and twenty seconds if you do not find the key from the correct Jigsaw Box."
The television turned off again leaving Morgan to get up and look for the Jigsaw Boxes. The first one was in his room which he presumed was the bathroom and he stuck his hands in it. The pain was tolerable for Dexter and he pulled out a key, only to realize it didn't fit the lock. Billy laughed before the Bay Harbor Butcher walked upstairs, barely missing the Pig looking behind a corner while crouched.
Another wrong key and a laugh as Morgan found another Jigsaw Box in what he assumed was the Killer's planning room. He realized something had happened when he didn’t hear the ticking anymore. Dexter turned to see Amanda Young in her full Pig outfit. She clicked her hidden blade out and roared as she lunged, the Bay Harbor Butcher barely getting out of the way in time. He quickly used his jujitsu training to it's full potential and unleashed as good of a beat down as he could while almost blind, causing Amanda to squeak in pain repeatedly.
Morgan ran downstairs while she recovered, the final Jigsaw Box in a room that had a closed metal door. He went as fast as he could and got the key out, finally removing the reverse bear trap as Young lunged again. He judo flipped her this time and went into the freezer, finding his hunting knife in a pig's carcass and his garrote along with his syringe on a crate.
Dexter crouched down to avoid detection as he tried to remember the lay-out for a sneak attack which proved useless when the Pig stabbed him in the back. Yelling in pain, he elbowed her but Amanda grabbed his leg and plunged the hidden blade into his thigh. Desperate, he stomped hard on her hand with a audible snap as she squeaked. Limping away, he went into the basement and tore off some of his pants to treat his wound.
Morgan hid in a locker and waited for her. Sure enough, Young crouch-walked down the stairs and opened the opposite locker. He rushed out and wrapped the garrote around her neck, sending her into a panic as she felt herself losing conciousness. She slamned into a wall and turned around to stab nothing. He pulled his hunting knife out and stabbed her good arm before being sent backwards with a backhand.
Amanda slashed his chest with the hidden blade but he grabbed her arm afterwards and pulled hard, dislocating it. This seemed to be the first thing that incapacitated her and Dexter sliced into it. Now groaning on the floor, she couldn't prevent him from shoving the syringe in her neck. Her veins filled with tranquilizer as she fell unconscious.
He only thought one thing. She started this game, now it's time for me to finish it.
The Pig woke up groggily but without her mask. She realized something was wrong when she couldn't move. Pictures of her previous test subjects were on the walls along with her reverse bear trap. She only felt shrink wrap as the Bay Harbor Butcher opened up a bag of tools, pulling out a hacksaw. He then stood over her with his hunting knife raised and held up her mask.
"Hello Jigsaw, don't worry I kept your mask safe."
"I'm not Jigsaw, I'm his apprentice and you, you are just meat, unworthy of winning the game."
"Is that so? I thought I won and even though you aren't who I was expecting, I know who you are Amanda."
"You don't know anything! You waste your life on petty murders while our games required some effort."
"Well, those wounds you gave me are troublesome and I wouldn't say that a self-harming junkie turned glorified serial killer isn't wasting her life."
"He will find you and he will test you again! This time with no escape!"
"But not now."
Dexter plunged the knife into her chest, puncturing her heart. Amanda glared at him with hate before her eyes rolled back. He pulled it out and cleaned it before grabbing the hacksaw, starting his routine with the neck.
The waves were calm as the trash bag that contained what was left of Amanda Young was thrown into the sea. Dexter Morgan slowly walked away, making the dock's boards creak. She hadn't been the first to wound him and she certainly wouldn't be the last. All in all, just another night.
While Amanda Young was a great ambush killer and trap-maker, she suffered in a direct fight. Dexter Morgan's martial arts training and experience in direct fights enabled him to get around her longer blade and superhuman physicality. His knowledge of anatomy also helped immensely to end the fight quickly and he was smart enough to easily get out of the reverse bear trap.