Boxes in the Basement

Hidelbert Preston was a normal fifteen year old. He hated his father once a week, his mother twice. He couldn't stand Aristides, the ten year old little brother, yet if you asked him he'd say that he loved the little kid. Today was a "I hate my father" day. Unfortunately it was also a "I hate my mother day" and damned Aristides was being annoying as hell. All Hidelbert wanted was to go to the Halloween party.
"But all the kids are going!"
"If all the kids jumped off a bridge would you jump too?"
"But I already have the costume!"
"Maybe you should have consulted your mother and I before buying it, then."
"But.. Mom! I'm Fifteen! Tell dad I can go!"
"If dad says no, then no it is."
It never went anywhere. Dad was already back to his newspaper, and mom was more interested in the soap opera. Aristides was running around the house, dressed in his Mega Man costume, shooting nerf balls to whatever moved : mostly the dog, but once or twice his older brother. Hidelbert just turned his back on the smaller kid and went into the basement. Dad didn't like him to go down there, but it was the only place in the house where he could feel at peace. He went down the stairs, pushed the light cord and sat between the bookshelf and the Christmas decorations, as always. Picking a book at random, he opened it and tried to read. Anger wasn't letting him focus, and after a few minutes of reading the first sentence over and over again, he threw the book into the far reaches of the basement. Hidelbert had been down there countless times, but he never explored the room. It was as big as the rest of the house, filled with books, gardening tools, old clothes, assorted computer parts, and lots and lots of boxes, "Zachary Preston personal effects" written on them. Above the handwritten letters, a shield Hidelbert had learned was from dad's old military division. Once he had asked mom about it, and she made him promise he would never ask dad about it. "Dad was in the army long ago. He left when he met me, and he doesn't like to remember those times" "Why does he keep those boxes then?" Hidelbert wanted to ask, but something in the way mom's face turned sad while she spoke of it made him change his mind. The shield itself was spooky : a raven holding a skull in it's claws.
Since he was hating both his parents that day, he decided to open one of the boxes and see what was it that his father kept. All boxes were numbered, and he decided to go for box 3, because he liked the number. It was a regular cardboard box, sealed with tape. He carefully ripped it open, revealing a bunch of simple notebooks. He grabbed the first one, opened it randomly and read :
"subject 4 still shows a strong appetite and no signs of fatigue. Test subject 5 almost doesn't eat and refuses to respond when questioned". He flipped a few pages and read : "Kludsu mated with Amberlea again last night. After seeing the tapes it seems as if it was Amberlea that lured Kludsu into her room, even after the talk we had last night. I believe she wishes to reproduce. If she finds the formula I shall have to recommend that she is euthanized". He grabs another notebook, from three months later, opens randomly again and reads "Amberlea still refuses to eat. It's been one month since we had to kill Kludsu. We've been force feeding her and she bit a technician yesterday. He will now be referred as test subject 23. He is stable so far, but shows signs of fatigue. I checked the records and test subjects survived for a average of 42 hours after being bitten. The longest is still test subject 5, that survived for 89 hours."
Hidelbert was each time more morbidly curious. It seemed that his father had been researching with humans, under government jurisdiction. But human testing was forbidden. And who was Amberlea? Was she human too? If so, why would her bite kill? He looked for box 1, opened it and searched for the first of the notebooks. Opening it on one of the first pages he read : "... all the ingredients. We should be ready to begin the summoning in two days". A few pages ahead : "Success. We summoned one. Doctor Ramul named him Zardox." Hidelbert skimmed over the entire notebook, and found nothing on what he was searching so he picked another one, and another one, until he found a entry about her : "I named her Amberlea. She is a perfect example. Her fangs retract, and she looks human." The rest was mostly clinical information and didn't matter to him.
He put the notebooks back into the box, closed it and looked around. The boxes were numbered from 1 till 28, and 4 boxes with letters : K, R, S e Z. He picked box K and opened it. He jumped back and gave a very unmanly scream when he saw the bones inside. He took several deep breaths and looked again. The bones looked as if they had been thrown inside the box without care. The skull was buried in the other bones, and Hidelbert could only see it's top. So he closed his eyes and reached to pull it out. It was almost human, if it were not for the jaw. The canines were as big as Hidelbert's thumb and hollow. He dropped the skull inside the box and was about to close it again when he saw something shinning inside. He grabbed it and saw that it was a ornate metal bracelet with the name 'Kludsu' on it. It reminded hm of something but he couldn't remember what. He put the bracelet in his pocket and closed the box. He then turned around to find a pair of shadows standing between him and the door.
Again he screamed, until he realized it was just mom and dad probably alerted by the noise before. Dad was sad, with a disappointed look on his face. "How many times have I told you I don't like you coming down here?"
"Dad... What was it that you did for the military?"
"NONE OF YOUR BUSINESS!"
"TOO LATE FOR THAT DAD! I read the notebooks. Human experimenting? And what was Kludsu? Was Amberlea a beast too?"
Dad slapped Hidelbert with all his strength, sending the teen to the floor. Mom was standing next to dad, silently, looking to the floor.
"Don't you dare calling her a beast!"
"They weren't human. You said so yourself! What were they? Animals?"
Mom looked at him, shock in her face. She lift her hand, as if to slap him, and Hidelbert remembered why was it that the metal bracelet he saw on the box seemed familiar. Her mother had one too. He couldn't see it from here, but he felt sure he knew what was written on it : Amberlea. Dad was crying now, holding his son by the shoulder : "This.. You shouldn't, you.. DAMN YOU STUPID KID!"
He escaped his father's clutch and pulled Mom's arm down with one hand, removing the bracelet with the other. Dad kicked him in the chest, throwing him to the floor "FUCK!" he screamed "WHY YOU FUCKING BRAT?"
The basement door opened and Aristides looked down, still in his costume, as shoot a nerf ball to Mom. She had been silent since Hidelbert removed the bracelet, a smile forming one her lips, slowly. When the ball hit her she turned her torso to the door, without moving her feet, opened her mouth, revealing huge teeth and with hunger in her eyes, she jumped. In one movement she grabbed the younger kid's head, jerked it to the side and stuck her fangs on his neck. After draining one, she jumped back to the floor, grabbed dad by the neck, and laughing, blood dripping from her teeth, covering her face and dress, lifted him. Dad was scared beyond words while she spoke, slowly "You thought you could keep me constrained forever? Sooner or latter you would die. This stupid kid only sped it up. And as a reward, he shall die last." She opened her mouth to a abnormally immense size and bit half of dad's head off. That was the last thing Hidelbert saw before fainting.