Gawain knight of the sun: actually the idea came from another anime called Mirai Kuriyama but I just looked up and yeah it is more like that thank you I never would have gotten that list of abilities he could have if I didn't look that up.
Harry led the headmaster down to the Chamber of Secrets after both hearing his confession about the blood magic and statue he had demanded to be taken into the chamber. Harry was surprised he had never seen the headmaster acting so serious. He found it easier to speak parseltongue this time and get down to the chamber. Dumbledore strided ahead of him when they reached the pole of rubble caused by the archway collapsing. With a mere flick of his wand he had turned the rubble into a stone arch once more. Harry gaped at the powerful display of magic, and he was reminded how difficult it was for him to make a simple blade of blood.
They entered the study of Slytherin cautiously it seemed the only reason Harry hadn't been attacked by the protections when he first entered was because of the fragment of Voldemort fooling the ward that only allowed those who held the family magic of parseltongue.
"But professor there is no way Slytherin was the only parseltongue right? I mean there must be others around the world?" Harry asked, he remembered after they found out about parseltongue, Hermione had gone on rant about how it was impossible for only his family to have that even a single child being born outside the family centuries would have caused others to gain the ability, or how there were tales in Africa of people being able to speak to snakes. She refused to believe the Slytherin line was the only one with parselmouths in the world.
"There are my boy, but it seems he made it so they had to traces of both his blood and the ability to speak Parseltongue to be able to enter."
"But I am not related to Slytherin!" Harry denied slightly alarmed, but to his surprise Dumbledore chuckled.
"Do not worry my boy you would be hard pressed to find a wizarding family that does not have connections to at least two of the founders, it is the second ability that makes it difficult to enter." he said picking up a book and checking it over with his wand to make sure it wasn't cursed. He opened the book and frowned it wasn't cursed but it did entail how to drain a demon of it's power to add it to your own, and involved the sacrifice of a hundred warriors. He flipped through the book to see if there was anything about stopping it or any counters. Seeing none he destroyed the book he had no doubt if Voldemort got his hand on this at best they would have a demonic dark lord at worst he could accidentally summon something he wasn't ready to fight and doom them all. He saw Harry reaching for a book and froze him in place.
"Sorry Harry but the book is cursed." he told the young boy as he levitated the book away from Harry, before releasing him.
"It's alright professor I suppose after this I should not to just pick up and random book." he felt very foolish now, not two days after he learned the dangers of cursed books he was now randomly picking them in the study of one the darkest wizards to ever live.
"We all make mistakes Harry, never forget that." Dumbledore told him and it seemed like he was remembering something.
He shook his head snapping himself out of his reminiscing. "But I digress." he flicked his wand and several books in sight began to glow various colors. "These are the cursed books so do not touch them, I will take them back to my study to look them over." Harry nodded and began to walk around randomly, occasionally picking up a book or two he even found an interesting one on fire magic. When he asked if he could keep it for a while Dumbledore chuckled fondly and said he remembered finding this book when he was young and that he may have even had a copy up in his study.
Harry put the book in his bag and ended up walking a familiar path. In front of him once more was the statue and once more he felt drawn to it. Placing his hand on it again he found himself back in the same void as before.
"So you return and with much more to offer this time." the voice mused and Harry could almost hear the hunger in it's voice.
"Wh-what can I gain this time?" he asked, a small desire for more rising up inside him. Riddle was only a few years older yet he knew enough about magic to make a living diary to complete his work in chamber.
The voice said nothing but once more his eyes burned and a screen appeared in front of him. He noticed something strange though there were less branches of magic than last time. Before he could say anything the statue answered his unasked question.
"As you delve into a certain branch of magic other branches become slowly cut off the deeper you go the harder it is to learn other branches."
"So it would be like a master of fire magic trying to learn water magic?" asked Harry trying understand, he supposed it made sense if he learned dark magic than light magic would be harder to learn.
"It seems you have gotten smarter." the voice said offhandedly and Harry assumed that meant he was correct.
Harry almost went straight to blood magic before he paused and decided to read some of the others. He pressed fire magic and another screen came up.
Infernal whip: a whip of fire that burns opponents to crisp, especially effective on undead.
Flame cloak: a spell that covers the user in second skin of fire that burns opponent that get to close.
Those were only two he could see and flame cloak was blacked out meaning he couldn't get it. He frowned and went back to the main screen and went to the blood magic. This time there several spells but only one was lit up. It was called.
Protection of blood: stops blood from being used against you in or without your permission.
This interested Harry a lot as he didn't want someone stealing his blood and making a fake of him or controlling him nodding he bought the item. The voice chuckled once more.
"It seems you have learned some patients this time actually reading them before buying. It is shame you don't want to buy anything else." Harry didn't bother to wonder how it knew that, it could read his mind. But he was curious about one thing.
"Where did I get the new demons blood I don't remember picking any up and there isn't another fragment of Voldemort in me. Is there?" he asked the last part alarmed he just got rid of the first piece he didn't want a second.
The voice chuckled once more. "No but when you slayed the basilisk you took in all of the demons blood within and destroy the diary did the same. You were in to much pain to notice the first and weren't paying attention for the second. Now this conversation bores me. Begone!"
Harry found himself back in the study standing in front of the statue once more. "Ah so this is the statue you found Harry?" Harry turned around to see Dumbledore coming around from behind a bookshelf.
Harry nodded nervously, did he see him touch the statue? "Yes sir."
Dumbledore looked at the statue for a moment before turning to Harry. "Do you know what this is?" he asked peering at the boy over his half moon glasses.
Harry shifted uncomfortable under the seemingly all knowing gaze of Dumbledore. "No sir I just touched it and-"
"Found yourself in a void with a seemingly all knowing voice who offered you powers in exchange for demon's blood?" Dumbledore finished for him and Harry looked at him alarmed. How did he know? "It is called a watcher of time, an immortal all knowing creature perhaps even a god. But do not worry it is not evil but rather just is. It does not care for our laws or morals, it would give Voldemort the power to the rule the world just as quickly as it would give you the power to save it." Dumbledore shook his head and turned away from the statue. "Trust me Harry all things come with a price and it will always be paid, whether for better or worse." he said grimly yet Harry thought he heard an undertone of regret.
He began to leave the study. "We can return here at a later date but for now we should make sure there are no other dangers in the chamber itself."
"Professor?" Harry called as they approached the body of the basilisk.
"Yes my boy?" Dumbledore asked as he waved his wand over the basilisk.
"The watcher it said the Basilisk was a demon but nothing Hermione found even hinted at that."
"You wished to know why there was demon blood in a non demonic creature?" Dumbledore said as he frowned as he got a response from one of his spells. "It seems Salazar fed the basilisk demons blood to make it grow faster and larger than normal." he told Harry. "And I believe I have found out why no one has been able to find the chamber."
"Why is that professor?"
"It was tied into the wards as another part of the castle meaning while everyone was searching for a weakness in the wards or hide corridors we never thought that the wards themselves would hide the chamber. It is quite ingenious actually a precursor to the-" Dumbledore was cut off by a clicking sound the was very familiar to Harry after his jaunt in the forest.
"Harry get behind me!" Dumbledore ordered as the spiders drew near. They were massive the same size as the ones in the forest but they were different they had rocks embedded in them.
"Acromantula!" Harry cried leveling his wand against the spiders but Dumbledore shook his head.
"Much worse I'm afraid, Kyklops Demon earth spiders a single one of these are more deadly than a hundred Acromantula. They reproduce just as fast as them and in a year there can be a hundred of them in two a ten thousand. Luckily if they are starved of food they will resort to eating each other, if I had to guess I would say the Basilisk was put here to keep them trapped."
"And I set them free." Harry muttered looking down, it was all his fault.
"Do not blame yourself Harry you had no idea what you were doing and Tom left you with no choice." Dumbledore said trying to banish any thoughts Harry had of this being his fault. There was never even a hint of something like this being down here.
Dumbledore lashed out with a spell that sliced through a dozen of them with ease, before turning around and burning a dozen more that were trying to sneak up behind them. Harry tried to help by throwing out a bombarda at any stragglers that Dumbledore missed.
"GET DOWN!" Dumbledore ordered as the number of spiders increased exponentially. Harry fell to the floor immediately and just in time. Dumbledore raised his wand. "kónguló eyðileggingu!" he incanted and a dome of light emerged from his wand. Similar to the spider repelling charm he used in the forest except instead of pushing them aside it completely destroyed them. When all the spiders were destroyed he pointed his wand at the breach where they entered and summoned the pillars that were destroyed by the basilisk before he transfigured it into a steel wall.
Harry looked at the new wall in confusion. "But professor I thought that transfiguration can't actually change an object's durability or traits only make it seem like it does." McGonagall had explained as if you turned a needle into a matchstick it wouldn't ignite because it was still a needle it may feel like a matchstick, it may look one, taste like one but in the end it was still a needle.
"That is true Harry but what I did was not Transfiguration but rather alchemy the art of permanently changing matter." Harry nodded remembering reading about that when they had found out who Nicolas Flamel was. "Now let us return to the castle, I have plenty work to do."
The blood immunity thing that seems like something that would exist. Now it is not perfect there are ways around but it basically make it impossible to use to resurrect voldemort and I always imagined Dumbledore and Voldemort both protecting themselves against such things. And his immunity can work against as you will later see.
also Slytherin is a dark wizard in my story but he also cared for his students so he put the basilisk there to hold back the spiders because he knew he couldn't stop them. he sees the demons as a bigger problem than the unworthy (in his eyes) muggleborns.