When Rokuko grinned, the deadlock trio turned up.
"What's this here? What are you bothering with 695?"
"Gue gue, here even though you're the lowest ehhh?"
"Yeah! Don't you know what to say to your superiors?"
Rokuko turned towards them, but she was smirking at them.
"Oh my. For what reason are you all here? What rank did you get?"
"Uwaah, what a gross face. Did your core melt from being talked to by Tou-sama? I went out of my way to let you know that you don't belong here. Me? 321st, fufufu, I went up three places ye know?"
"322nd, gekokoko. I passed 650."
"310th! I'm the best of us three!"
"Oi, 653 getting all cheeky? So, 695. You?"
... Fu. Rokuko laughed haughtily. Then, she spoke with a triumphant look.
"... Nn? Sooorry, what was that?"
"210th! Fufufu, I passed you! I passed all of you!"
"Geko? The eternal lowest ranked 695 in 200th, this is an illusion riiight?"
"Look right there then! Take a goooood look, it says 210th, 695!"
Rokuko pointed at the table. It really did say 695 in 210th place.
"No way!? Hold up, is something wrong with the display!? How could the lowest ranked 695 be that high up!?"
"I'm not at the bottom anymore! I'm 210th. Right, I'm higher ranked! Add [No.] to the 650!"
"I absolutely refuse. I definitely don't recognize you being 210th. Weren't you just saying some shit about not using [No.] for us?"
"Ah, that's right, huh."
I guess [No.] isn't important, Rokuko thought, changing gears.
"But what the heck. How'd 695 pass us after so many years of us saving up DP? Father's mistake?"
"Father's mistake... no waaaay. Maybe she cheated?"
"Geko geko, yeah, cheated! She's a cheater!"
Core 651 shouted out [Cheater! Cheater!] with its loud voice.
Rokuko, who had been the lowest rank until now, suddenly rose to 210th place. Moreover, the rankings weren't based on the amount they earned in a given year. It was based on the amount of DP they'd saved since their birth... it was natural for cheating to be suspected.
Because of that, the cores who were surpassed by that low ranked Rokuko got hooked on by his voice and started paying attention.
"But what kind of cheating could she have done?"
"Didn't she get some DP from the [Betrayer]? A fixed dungeon battle or something..."
"Come to think of it, there was something said about her winning against No. 112 a bit ago... how did the lowest ranked core win? Does that mean that No. 112 is a co-conspirator...?"
Ah, what they're talking about is actually close to the truth.
Huh? Does that mean I cheated? Did I cheat? It was illegal?
"Confess! Now, how did you cheat, 695!?"
"I-I didn't, c-cheat though!?"
"Uwaah, you're obviously trembling. How suspicious... nyujururu."
Not knowing how it turned into her doing something wrong, Rokuko's eyes started to spin, growing hot. She looked like she was about to cry.
"Stop talking, you unsightly worm."
A cold voice projected out from somewhere. With those words, the area grew silent.
A fiery red-haired girl appeared.
"Use [No.], 650. Is that not common courtesy? I am a higher rank than you, and you and I are not close with each other."
Core 666. The first in the 600 Series to take on human form, she was an excellent core.
She was also the youngest in Core No. 6's Demon King Faction.
"Guh-No. 666! Say something to 695 too!"
"Why should I?"
"Why!? This cheater passed you!"
"She did not pass me."
When looking towards the spot Core 666 pointed towards, it said [180th, 666].
She pushed aside many people, making her way past the 200s.
"B-but! She cheated to raise her rank! Yeah, she definitely got some from 89!"
With the funds for the dungeon battle and the inn fees Rokuko received from Haku, as well as the DP she got as tips, he wasn't necessarily wrong.
-Crap, was that illegal?
Rokuko was even more flustered now.
"Foolish... then shouldn't you just raise your rank the same, through [Cheating]?"
"Haah!? W-what're you saying!? Are you stupid!?"
Core 650 shouted, saying it was out of the question.
Meanwhile, Core 666 simply sighed.
"Not at all. If the placement was recognized by father, it isn't cheating, right? Is it cheating to earn DP through means you can't do yourself? Even if the pretext is extreme."
"Guh... r-right, 666 gets No. 6-sama's leftovers like how Rokuko does, so it's not like she would speak again here huh, soooorry, hohoho."
With a flash, Core 666 pointed a magic sword clad in flames towards the middle of Core 650's eyes. It happened in an instant, so Core 650 wasn't able to react in the slightest.
"If you insult Jiji-sama... I will slaughter you like a pig!"
"Hiii!? W-what!? Kill!? Y-y-you wouldn't actually-!"
Even while saying that, Core 650 (the snake) quickly retreated to Core 651 (the frog) and hid behind him. Core 666's sword suddenly vanished and she spoke with a nonchalant look on her face.
"So the snake is a wimp? What do you think, 695?"
"Eh? Ah, un, you could... say that?"
"Yeah.... So, wimp?"
"Shaaa!! So cheeky, even though you're just 695!"
"Eh, wait!? Why did it turn into me saying that!?"
Hmph. Core 666 snorted.
Core 666 somehow laid the blame on her, but for some reason she felt less nervous.
-By some chance, did she just help me?
Core 666 just noticed something after looking at Rokuko. As for what she was looking at, it was the red ruby and orichalcum ring on her left hand.
"... 695. That's a beautiful ring."
"Eh? Ah, this? Ehehe, in truth, I got a master you know? Then, I got this ring as a present from him!"
"Heeh, from your master huh... seems expensive. If I'm not wrong... that's orichalcum, right?"
"Eh, ah, un. Yeah."
"Could I take a closer look?"
"Eh? Nnn, c-can you see it like this?"
Rokuko completely ignored the roars coming from Core 650, who was still hiding behind Core 651, and held her hand out to Core 666.
She took her hand and looked at the ring... it was a ring that encased an orichalcum band with pure ruby, one without any mars. Core 666 observed it carefully. 50,000,000 DP wouldn't be enough, it was a treasure worth at least 100,000,000 DP.
"Why didn't you turn that ring into DP?"
"Eeh!? No way, t-this ring is important, I got it from my master. There's no way I could!"
"But if you did, wouldn't your ranking go up quite a lot?"
-Even more than mine.
Core 666 stared at Rokuko intensely.
As for Rokuko, she knew that Kehma had made it with a small amount of DP, so she didn't think that it would turn into much DP. Well, she didn't intend to do that since it was her important ring (present), though.
"No, don't wanna."
Hearing Rokuko's answer, Core 666 let go of her hands.
"So wasteful, 695. Really, just a bit... just a tiny bit, I want to break you."
"Please don't!? It doesn't sound like a joke coming from 666!?"
When Rokuko said ... even though it was like how humans would refer to someone by their first name, Core 666 didn't particularly take it as anything bad. 
Instead, she laughed with a smile on her face.
Then, she spoke.
"Therefore, 695. I request to have a duel with you."
Remember that in Japan, it's mostly presumptuous to call someone by their first name. It can be anything from rude to intimate. Dungeon cores' names are structured with XXX for the number, where I am translating as the [No.] portion of the name. In their-the dungeon cores'-culture, it is like an extra honorific (like san, kun, etc) that is used to make it more formal and not so similar to using someone's first name. It might be a little confusing, so sorry about that