Wow. That, that took a long time. 

From my ability, I gained some helpful memories, some painful memories, and some boring memories. Mainly just boring memories, though. Mainly way too many boring memories. I feel like I'm supposed to be so excited about being reincarnated and everything but having all those experiences just makes things feel so much more... boring.

...

I guess for now I'll work on getting out of here.

The segmented parts of my body unfurl, and the first thing I see is light. It's surprisingly light. I feel like I should've already been found and sealed away or something since those memories should have taken a while to gain. Or did they happen instantly? Well, no. It definitely took some time. Otherwise, I'd still be in that cave. 

So in conclusion, I didn't get sealed, but definitely found. As for why I say found, it's because I'm levitating in an energy field atop a pedestal in this small, circular room. The lack of any restraints on me and general openness(?) of the place makes me think I'm used for something. There are two sets of stairs at my sides, one rising and one descending.

Aside from those, there aren't really any other remarkable features, so I inspect those.

I shift my weight to my legs and slide off the energy field, and immediately after latticed gates slam down on the exits. From the floor rise earthen creatures ranging from wolves to crows to serpents, each marked in some form by crimson sigils. 

They pace around scanning the area for something, but apparently that something isn't me. Although I'm pretty sure this should be a situation where bystanders get mauled, it's like they see me as even less than that. Or do they not even see me, to begin with? Waving my hand in front of one causes its eyes to glance at me, but that's about it. I guess I'm just overlooked.

While the probably search and destroy mission was continuing, I hear some faint crashing noises from the stairway going down. I weave my way through the creatures guarding the entrance and see a disheveled pair of pajamas pull itself up a lower flight. "Yawwn, why did they have to come now..." I can also see some random beakers and stains covering it, and it takes a moment for me to realize there's an actual human under that walking bedroom nightmare.

Seemingly matching the description, it lifts its hoodie to reveal a young teenage girl. Though a "human" girl may be too specific. Her skin's unhealthily paled, and when she peers up at me, light reflects back bright, red eyes. I can't actually see her teeth, but this speaks a lot like a vampire.

As for her reaction to me, her sleepy eyes widen a bit.

"Who the..." Pointy canines confirmed. I'm pretty sure she's a vampire. Clearly abruptly woken, she rubs her eyes as her expression shifts to a venomous glare. "Who the hell are you supposed to be? I'm pretty sure even those goddamn Doves wouldn't stoop to something this low".

Mmm, see, I think you're insulting me. Although I'm not sure what you mean by "doves," I don't feel that incentivized to be co-operative towards someone that I think is insulting me. 

Let's test a landmine. "Okay, I'm not one to judge, but that vulgar language automatically makes me assume you're over thirty."

The offensive and apparently accurate statement irritates her even more.

"Shut, shut up." She walks up the rest of the stairs until we're at a level height. Sort of. She's still shorter than me by about two heads. "The only reason why you're still alive right now is because of these," she momentarily glares at a nearby bear, "stupid guardians. I don't know why they aren't attacking, but as soon as I set them to target you, you're dead."

I test the spaces between the bars of the gate, and my hand's able to slide cleanly through. "And walking up to someone you're threatening who may or may not have concealed weapons is a good idea how?"

"Don't bother, they're warded." I got knife-hands who would like to blade you farewell.

After she says so, I hear her muttering some words, the second of which is "dungeon core." Hm? Dungeon core? Pointing at the empty pedestal, I ask her, "Hey, so is this about the missing ball over there? And you're the owner of said missing ball?"

"What else would I mean?"

Oh. Okay... Status. 

The previous five-panel display gained a new addition, this one titled "Dungeon Core Abilities." In my titles, I also acquired one called "Living Dungeon Core."

...

How the... how the hell did I end up being mistaken for one? No, I'm literally being used as one. Just being mistaken for one doesn't make me actually function like one.

She's muttering something about guardians, which sort of forces me to put any theorizing aside. I scan over the rest of the menu, and conveniently, there's a button labeled, "Become Independent." 

Well, I'm not complaining. 

I select it.

Although I can't actually see what's happening on her side, her expression furrows in confusion, quickly morphing to anger. I'm guessing she got a notification or something saying "loss of access." To confirm, she yells, "WHAT THE HELL DID YOU DO??!!?"

After clicking the independence button, it felt like I was suddenly connected to this vast network of information. It would have been an absolute pain to sort through everything, but I feel like the magic system is taking most of the burden processing it all, making it much more use-able to a... "living dungeon core." 

"So, before anything else," I open the gates between us, "let's talk for a moment."

"LIKE HELL I WOULD!" I probably should've waited for her to calm down. Some sort of spell immediately rends through my torso, throwing my upper half across the room. "Owww... That, that was completely uncalled for. Can't you just, shoot later, think first, or something?" I push up the upper half of my torso to a leaning position. 

Oddly enough, when the shot was fired at me, I didn't try to dodge since there wasn't any sort of instinct warning me of death or injury. I guess that's from the intuition of my other memories? Although I'm happy that I don't seem to be dying, why would I let myself be shot in the first place? I'm pretty sure I don't enjoy pain or anything like that...

As I'm thinking about my possibly masochistic tendencies, my lower half that was so violently mutilated by a sadistic sociopath starts dissolving, turning into a translucent vapor and snaking back towards my body. I can feel my torso regenerating. So, yes. Seeing how this turned out I'm pretty sure "True Immortal" actually means I'm truly immortal. 

Well, that's really reassuring. I definitely can't be killed~

For her, she looks at the sight with confusion. "Wh-what? I've never seen any living creatures regenerate like that." She captures a bit of the mana flowing back to my body. "Hey! Don't just grab things, you don't even know what part that's supposed to restore!" I'm rudely ignored.

She molds it into a small ball and pops it into her mouth. "Oh, what the hell, you ate it?" I'm ignored again. "This mana, it's the same consistency as my dungeon?" She glances at the beasts. Furiously trying to understand the implications of everything.

"So, you eat mana? Like, you shoot a fireball at yourself for food or something?"

I think she's on the verge of connecting the dots between me and her precious dungeon core, but I'm impatient. I look towards the creatures and start summoning more. "Okay, knock her out or something. Apparently, she doesn't know the meaning of 'let's talk.'"

As the creatures close in on her from the front, back, and sides. I can see multiple flashy spells tearing through the beasts, but I guess a perk of being a dungeon core is summoning infinite creatures?

Ultimately she gets tired out.

Backed against a wall, I think I hear her mutter the word, "shit."